Update gnulib to a3a946f670718d0dee5a7425ad5ac0a29fb46ea1wip-gnulib-update

This fixes https://lists.gnu.org/archive/html/guile-devel/2021-04/msg00009.html

54 files changed, 1075 insertions, 302 deletions

diff --git a/build-aux/config.rpath b/build-aux/config.rpath
index 17298f234..4b7dc49c2 100755
--- a/build-aux/config.rpath
+++ b/build-aux/config.rpath
@@ -2,7 +2,7 @@
 # Output a system dependent set of variables, describing how to set the
 # run time search path of shared libraries in an executable.
 #
-#   Copyright 1996-2010 Free Software Foundation, Inc.
+#   Copyright 1996-2021 Free Software Foundation, Inc.
 #   Taken from GNU libtool, 2001
 #   Originally by Gordon Matzigkeit <gord@gnu.ai.mit.edu>, 1996
 #
@@ -25,7 +25,7 @@
 #   known workaround is to choose shorter directory names for the build
 #   directory and/or the installation directory.
 
-# All known linkers require a `.a' archive for static linking (except MSVC,
+# All known linkers require a '.a' archive for static linking (except MSVC,
 # which needs '.lib').
 libext=a
 shrext=.so
@@ -57,13 +57,6 @@ else
     aix*)
       wl='-Wl,'
       ;;
-    darwin*)
-      case $cc_basename in
-        xlc*)
-          wl='-Wl,'
-          ;;
-      esac
-      ;;
     mingw* | cygwin* | pw32* | os2* | cegcc*)
       ;;
     hpux9* | hpux10* | hpux11*)
@@ -72,9 +65,7 @@ else
     irix5* | irix6* | nonstopux*)
       wl='-Wl,'
       ;;
-    newsos6)
-      ;;
-    linux* | k*bsd*-gnu)
+    linux* | k*bsd*-gnu | kopensolaris*-gnu)
       case $cc_basename in
         ecc*)
           wl='-Wl,'
@@ -85,17 +76,26 @@ else
         lf95*)
           wl='-Wl,'
           ;;
-        pgcc | pgf77 | pgf90)
+        nagfor*)
+          wl='-Wl,-Wl,,'
+          ;;
+        pgcc* | pgf77* | pgf90* | pgf95* | pgfortran*)
           wl='-Wl,'
           ;;
         ccc*)
           wl='-Wl,'
           ;;
+        xl* | bgxl* | bgf* | mpixl*)
+          wl='-Wl,'
+          ;;
         como)
           wl='-lopt='
           ;;
         *)
           case `$CC -V 2>&1 | sed 5q` in
+            *Sun\ F* | *Sun*Fortran*)
+              wl=
+              ;;
             *Sun\ C*)
               wl='-Wl,'
               ;;
@@ -103,13 +103,24 @@ else
           ;;
       esac
       ;;
+    newsos6)
+      ;;
+    *nto* | *qnx*)
+      ;;
     osf3* | osf4* | osf5*)
       wl='-Wl,'
       ;;
     rdos*)
       ;;
     solaris*)
-      wl='-Wl,'
+      case $cc_basename in
+        f77* | f90* | f95* | sunf77* | sunf90* | sunf95*)
+          wl='-Qoption ld '
+          ;;
+        *)
+          wl='-Wl,'
+          ;;
+      esac
       ;;
     sunos4*)
       wl='-Qoption ld '
@@ -171,15 +182,14 @@ if test "$with_gnu_ld" = yes; then
       fi
       ;;
     amigaos*)
-      hardcode_libdir_flag_spec='-L$libdir'
-      hardcode_minus_L=yes
-      # Samuel A. Falvo II <kc5tja@dolphin.openprojects.net> reports
-      # that the semantics of dynamic libraries on AmigaOS, at least up
-      # to version 4, is to share data among multiple programs linked
-      # with the same dynamic library.  Since this doesn't match the
-      # behavior of shared libraries on other platforms, we cannot use
-      # them.
-      ld_shlibs=no
+      case "$host_cpu" in
+        powerpc)
+          ;;
+        m68k)
+          hardcode_libdir_flag_spec='-L$libdir'
+          hardcode_minus_L=yes
+          ;;
+      esac
       ;;
     beos*)
       if $LD --help 2>&1 | grep ': supported targets:.* elf' > /dev/null; then
@@ -198,11 +208,13 @@ if test "$with_gnu_ld" = yes; then
         ld_shlibs=no
       fi
       ;;
+    haiku*)
+      ;;
     interix[3-9]*)
       hardcode_direct=no
       hardcode_libdir_flag_spec='${wl}-rpath,$libdir'
       ;;
-    gnu* | linux* | k*bsd*-gnu)
+    gnu* | linux* | tpf* | k*bsd*-gnu | kopensolaris*-gnu)
       if $LD --help 2>&1 | grep ': supported targets:.* elf' > /dev/null; then
         :
       else
@@ -325,10 +337,14 @@ else
       fi
       ;;
     amigaos*)
-      hardcode_libdir_flag_spec='-L$libdir'
-      hardcode_minus_L=yes
-      # see comment about different semantics on the GNU ld section
-      ld_shlibs=no
+      case "$host_cpu" in
+        powerpc)
+          ;;
+        m68k)
+          hardcode_libdir_flag_spec='-L$libdir'
+          hardcode_minus_L=yes
+          ;;
+      esac
       ;;
     bsdi[45]*)
       ;;
@@ -342,33 +358,20 @@ else
       ;;
     darwin* | rhapsody*)
       hardcode_direct=no
-      if test "$GCC" = yes ; then
+      if { case $cc_basename in ifort*) true;; *) test "$GCC" = yes;; esac; }; then
         :
       else
-        case $cc_basename in
-          xlc*)
-            ;;
-          *)
-            ld_shlibs=no
-            ;;
-        esac
+        ld_shlibs=no
       fi
       ;;
     dgux*)
       hardcode_libdir_flag_spec='-L$libdir'
       ;;
-    freebsd1*)
-      ld_shlibs=no
-      ;;
-    freebsd2.2*)
-      hardcode_libdir_flag_spec='-R$libdir'
-      hardcode_direct=yes
-      ;;
-    freebsd2*)
+    freebsd2.[01]*)
       hardcode_direct=yes
       hardcode_minus_L=yes
       ;;
-    freebsd* | dragonfly*)
+    freebsd* | dragonfly* | midnightbsd*)
       hardcode_libdir_flag_spec='-R$libdir'
       hardcode_direct=yes
       ;;
@@ -420,6 +423,8 @@ else
       hardcode_libdir_flag_spec='${wl}-rpath ${wl}$libdir'
       hardcode_libdir_separator=:
       ;;
+    *nto* | *qnx*)
+      ;;
     openbsd*)
       if test -f /usr/libexec/ld.so; then
         hardcode_direct=yes
@@ -515,7 +520,12 @@ case "$host_os" in
     library_names_spec='$libname$shrext'
     ;;
   amigaos*)
-    library_names_spec='$libname.a'
+    case "$host_cpu" in
+      powerpc*)
+        library_names_spec='$libname$shrext' ;;
+      m68k)
+        library_names_spec='$libname.a' ;;
+    esac
     ;;
   beos*)
     library_names_spec='$libname$shrext'
@@ -534,19 +544,18 @@ case "$host_os" in
   dgux*)
     library_names_spec='$libname$shrext'
     ;;
-  freebsd1*)
+  freebsd[23].*)
+    library_names_spec='$libname$shrext$versuffix'
     ;;
-  freebsd* | dragonfly*)
-    case "$host_os" in
-      freebsd[123]*)
-        library_names_spec='$libname$shrext$versuffix' ;;
-      *)
-        library_names_spec='$libname$shrext' ;;
-    esac
+  freebsd* | dragonfly* | midnightbsd*)
+    library_names_spec='$libname$shrext'
     ;;
   gnu*)
     library_names_spec='$libname$shrext'
     ;;
+  haiku*)
+    library_names_spec='$libname$shrext'
+    ;;
   hpux9* | hpux10* | hpux11*)
     case $host_cpu in
       ia64*)
@@ -582,7 +591,7 @@ case "$host_os" in
     ;;
   linux*oldld* | linux*aout* | linux*coff*)
     ;;
-  linux* | k*bsd*-gnu)
+  linux* | k*bsd*-gnu | kopensolaris*-gnu)
     library_names_spec='$libname$shrext'
     ;;
   knetbsd*-gnu)
@@ -594,7 +603,7 @@ case "$host_os" in
   newsos6)
     library_names_spec='$libname$shrext'
     ;;
-  nto-qnx*)
+  *nto* | *qnx*)
     library_names_spec='$libname$shrext'
     ;;
   openbsd*)
@@ -625,6 +634,9 @@ case "$host_os" in
   sysv5* | sco3.2v5* | sco5v6* | unixware* | OpenUNIX* | sysv4*uw2*)
     library_names_spec='$libname$shrext'
     ;;
+  tpf*)
+    library_names_spec='$libname$shrext'
+    ;;
   uts4*)
     library_names_spec='$libname$shrext'
     ;;
diff --git a/build-aux/gitlog-to-changelog b/build-aux/gitlog-to-changelog
index de76f658d..9ff15f601 100755
--- a/build-aux/gitlog-to-changelog
+++ b/build-aux/gitlog-to-changelog
@@ -35,7 +35,7 @@
 eval 'exec perl -wSx "$0" "$@"'
      if 0;
 
-my $VERSION = '2020-04-04 15:07'; # UTC
+my $VERSION = '2021-02-24 23:42'; # UTC
 # The definition above must lie within the first 8 lines in order
 # for the Emacs time-stamp write hook (at end) to update it.
 # If you change this file with Emacs, please let the write hook
@@ -455,7 +455,8 @@ sub git_dir_option($)
           # If there were any lines
           if (@line == 0)
             {
-              warn "$ME: warning: empty commit message:\n  $date_line\n";
+              warn "$ME: warning: empty commit message:\n"
+                   . "  commit $sha\n  $date_line\n";
             }
           else
             {
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 86c7aba28..02480f6e9 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -720,9 +720,7 @@ EXTRA_libgnu_la_SOURCES += floor.c
 
 ## begin gnulib module free-posix
 
-if gl_GNULIB_ENABLED_ef07dc4b3077c11ea9cef586db4e5955
 
-endif
 EXTRA_DIST += free.c
 
 EXTRA_libgnu_la_SOURCES += free.c
@@ -2003,6 +2001,17 @@ EXTRA_libgnu_la_SOURCES += readlink.c
 
 ## end   gnulib module readlink
 
+## begin gnulib module realloc-posix
+
+if gl_GNULIB_ENABLED_61bcaca76b3e6f9ae55d57a1c3193bc4
+
+endif
+EXTRA_DIST += realloc.c
+
+EXTRA_libgnu_la_SOURCES += realloc.c
+
+## end   gnulib module realloc-posix
+
 ## begin gnulib module recv
 
 
@@ -2628,8 +2637,10 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's/@''GNULIB_SECURE_GETENV''@/$(GNULIB_SECURE_GETENV)/g' \
 	      -e 's/@''GNULIB_SETENV''@/$(GNULIB_SETENV)/g' \
 	      -e 's/@''GNULIB_STRTOD''@/$(GNULIB_STRTOD)/g' \
+	      -e 's/@''GNULIB_STRTOL''@/$(GNULIB_STRTOL)/g' \
 	      -e 's/@''GNULIB_STRTOLD''@/$(GNULIB_STRTOLD)/g' \
 	      -e 's/@''GNULIB_STRTOLL''@/$(GNULIB_STRTOLL)/g' \
+	      -e 's/@''GNULIB_STRTOUL''@/$(GNULIB_STRTOUL)/g' \
 	      -e 's/@''GNULIB_STRTOULL''@/$(GNULIB_STRTOULL)/g' \
 	      -e 's/@''GNULIB_SYSTEM_POSIX''@/$(GNULIB_SYSTEM_POSIX)/g' \
 	      -e 's/@''GNULIB_UNLOCKPT''@/$(GNULIB_UNLOCKPT)/g' \
@@ -2675,8 +2686,10 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's|@''HAVE_SETSTATE''@|$(HAVE_SETSTATE)|g' \
 	      -e 's|@''HAVE_DECL_SETSTATE''@|$(HAVE_DECL_SETSTATE)|g' \
 	      -e 's|@''HAVE_STRTOD''@|$(HAVE_STRTOD)|g' \
+	      -e 's|@''HAVE_STRTOL''@|$(HAVE_STRTOL)|g' \
 	      -e 's|@''HAVE_STRTOLD''@|$(HAVE_STRTOLD)|g' \
 	      -e 's|@''HAVE_STRTOLL''@|$(HAVE_STRTOLL)|g' \
+	      -e 's|@''HAVE_STRTOUL''@|$(HAVE_STRTOUL)|g' \
 	      -e 's|@''HAVE_STRTOULL''@|$(HAVE_STRTOULL)|g' \
 	      -e 's|@''HAVE_STRUCT_RANDOM_DATA''@|$(HAVE_STRUCT_RANDOM_DATA)|g' \
 	      -e 's|@''HAVE_SYS_LOADAVG_H''@|$(HAVE_SYS_LOADAVG_H)|g' \
@@ -2702,7 +2715,11 @@ stdlib.h: stdlib.in.h $(top_builddir)/config.status $(CXXDEFS_H) \
 	      -e 's|@''REPLACE_SETENV''@|$(REPLACE_SETENV)|g' \
 	      -e 's|@''REPLACE_SETSTATE''@|$(REPLACE_SETSTATE)|g' \
 	      -e 's|@''REPLACE_STRTOD''@|$(REPLACE_STRTOD)|g' \
+	      -e 's|@''REPLACE_STRTOL''@|$(REPLACE_STRTOL)|g' \
 	      -e 's|@''REPLACE_STRTOLD''@|$(REPLACE_STRTOLD)|g' \
+	      -e 's|@''REPLACE_STRTOLL''@|$(REPLACE_STRTOLL)|g' \
+	      -e 's|@''REPLACE_STRTOUL''@|$(REPLACE_STRTOUL)|g' \
+	      -e 's|@''REPLACE_STRTOULL''@|$(REPLACE_STRTOULL)|g' \
 	      -e 's|@''REPLACE_UNSETENV''@|$(REPLACE_UNSETENV)|g' \
 	      -e 's|@''REPLACE_WCTOMB''@|$(REPLACE_WCTOMB)|g' \
 	      -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
diff --git a/lib/canonicalize-lgpl.c b/lib/canonicalize-lgpl.c
index bf63355da..c6fef174c 100644
--- a/lib/canonicalize-lgpl.c
+++ b/lib/canonicalize-lgpl.c
@@ -21,7 +21,6 @@
    optimizes away the name == NULL test below.  */
 # define _GL_ARG_NONNULL(params)
 
-# define _GL_USE_STDLIB_ALLOC 1
 # include <libc-config.h>
 #endif
 
@@ -76,6 +75,12 @@
 # define __rawmemchr rawmemchr
 # define __readlink readlink
 # define __stat stat
+# if IN_RELOCWRAPPER
+    /* When building the relocatable program wrapper, use the system's memmove
+       function, not the gnulib override, otherwise we would get a link error.
+     */
+#  undef memmove
+# endif
 #endif
 
 /* Suppress bogus GCC -Wmaybe-uninitialized warnings.  */
diff --git a/lib/cdefs.h b/lib/cdefs.h
index a22ae6db2..90f97412a 100644
--- a/lib/cdefs.h
+++ b/lib/cdefs.h
@@ -38,7 +38,9 @@
        #if defined __has_attribute && __has_attribute (...)
    even though they do not need to evaluate the right-hand side of the &&.
    Similarly for __has_builtin, etc.  */
-#ifdef __has_attribute
+#if (defined __has_attribute \
+     && (!defined __clang_minor__ \
+         || 3 < __clang_major__ + (5 <= __clang_minor__)))
 # define __glibc_has_attribute(attr) __has_attribute (attr)
 #else
 # define __glibc_has_attribute(attr) 0
@@ -318,15 +320,17 @@
 #endif
 
 /* The nonnull function attribute marks pointer parameters that
-   must not be NULL.  Do not define __nonnull if it is already defined,
-   for portability when this file is used in Gnulib.  */
-#ifndef __nonnull
+   must not be NULL.  */
+#ifndef __attribute_nonnull__
 # if __GNUC_PREREQ (3,3) || __glibc_has_attribute (__nonnull__)
-#  define __nonnull(params) __attribute__ ((__nonnull__ params))
+#  define __attribute_nonnull__(params) __attribute__ ((__nonnull__ params))
 # else
-#  define __nonnull(params)
+#  define __attribute_nonnull__(params)
 # endif
 #endif
+#ifndef __nonnull
+# define __nonnull(params) __attribute_nonnull__ (params)
+#endif
 
 /* If fortification mode, we warn about unused results of certain
    function calls which can lead to problems.  */
diff --git a/lib/dynarray.h b/lib/dynarray.h
index 0e249422e..5db6ed95b 100644
--- a/lib/dynarray.h
+++ b/lib/dynarray.h
@@ -14,18 +14,267 @@
    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
-/* Written by Paul Eggert, 2021.  */
+/* Written by Paul Eggert and Bruno Haible, 2021.  */
 
 #ifndef _GL_DYNARRAY_H
 #define _GL_DYNARRAY_H
 
-#include <libc-config.h>
+/* Before including this file, you need to define:
 
+   DYNARRAY_STRUCT
+      The struct tag of dynamic array to be defined.
+
+   DYNARRAY_ELEMENT
+      The type name of the element type.  Elements are copied
+      as if by memcpy, and can change address as the dynamic
+      array grows.
+
+   DYNARRAY_PREFIX
+      The prefix of the functions which are defined.
+
+   The following parameters are optional:
+
+   DYNARRAY_ELEMENT_FREE
+      DYNARRAY_ELEMENT_FREE (E) is evaluated to deallocate the
+      contents of elements. E is of type  DYNARRAY_ELEMENT *.
+
+   DYNARRAY_ELEMENT_INIT
+      DYNARRAY_ELEMENT_INIT (E) is evaluated to initialize a new
+      element.  E is of type  DYNARRAY_ELEMENT *.
+      If DYNARRAY_ELEMENT_FREE but not DYNARRAY_ELEMENT_INIT is
+      defined, new elements are automatically zero-initialized.
+      Otherwise, new elements have undefined contents.
+
+   DYNARRAY_INITIAL_SIZE
+      The size of the statically allocated array (default:
+      at least 2, more elements if they fit into 128 bytes).
+      Must be a preprocessor constant.  If DYNARRAY_INITIAL_SIZE is 0,
+      there is no statically allocated array at, and all non-empty
+      arrays are heap-allocated.
+
+   DYNARRAY_FINAL_TYPE
+      The name of the type which holds the final array.  If not
+      defined, is PREFIX##finalize not provided.  DYNARRAY_FINAL_TYPE
+      must be a struct type, with members of type DYNARRAY_ELEMENT and
+      size_t at the start (in this order).
+
+   These macros are undefined after this header file has been
+   included.
+
+   The following types are provided (their members are private to the
+   dynarray implementation):
+
+     struct DYNARRAY_STRUCT
+
+   The following functions are provided:
+ */
+
+/* Initialize a dynamic array object.  This must be called before any
+   use of the object.  */
+#if 0
+static void
+       DYNARRAY_PREFIX##init (struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Deallocate the dynamic array and its elements.  */
+#if 0
+static void
+       DYNARRAY_PREFIX##free (struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Return true if the dynamic array is in an error state.  */
+#if 0
+static bool
+       DYNARRAY_PREFIX##has_failed (const struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Mark the dynamic array as failed.  All elements are deallocated as
+   a side effect.  */
+#if 0
+static void
+       DYNARRAY_PREFIX##mark_failed (struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Return the number of elements which have been added to the dynamic
+   array.  */
+#if 0
+static size_t
+       DYNARRAY_PREFIX##size (const struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Return a pointer to the first array element, if any.  For a
+   zero-length array, the pointer can be NULL even though the dynamic
+   array has not entered the failure state.  */
+#if 0
+static DYNARRAY_ELEMENT *
+       DYNARRAY_PREFIX##begin (const struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Return a pointer one element past the last array element.  For a
+   zero-length array, the pointer can be NULL even though the dynamic
+   array has not entered the failure state.  */
+#if 0
+static DYNARRAY_ELEMENT *
+       DYNARRAY_PREFIX##end (const struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Return a pointer to the array element at INDEX.  Terminate the
+   process if INDEX is out of bounds.  */
+#if 0
+static DYNARRAY_ELEMENT *
+       DYNARRAY_PREFIX##at (struct DYNARRAY_STRUCT *list, size_t index);
+#endif
+
+/* Add ITEM at the end of the array, enlarging it by one element.
+   Mark *LIST as failed if the dynamic array allocation size cannot be
+   increased.  */
+#if 0
+static void
+       DYNARRAY_PREFIX##add (struct DYNARRAY_STRUCT *list,
+                             DYNARRAY_ELEMENT item);
+#endif
+
+/* Allocate a place for a new element in *LIST and return a pointer to
+   it.  The pointer can be NULL if the dynamic array cannot be
+   enlarged due to a memory allocation failure.  */
+#if 0
+static DYNARRAY_ELEMENT *
+       DYNARRAY_PREFIX##emplace (struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Change the size of *LIST to SIZE.  If SIZE is larger than the
+   existing size, new elements are added (which can be initialized).
+   Otherwise, the list is truncated, and elements are freed.  Return
+   false on memory allocation failure (and mark *LIST as failed).  */
+#if 0
+static bool
+       DYNARRAY_PREFIX##resize (struct DYNARRAY_STRUCT *list, size_t size);
+#endif
+
+/* Remove the last element of LIST if it is present.  */
+#if 0
+static void
+       DYNARRAY_PREFIX##remove_last (struct DYNARRAY_STRUCT *list);
+#endif
+
+/* Remove all elements from the list.  The elements are freed, but the
+   list itself is not.  */
+#if 0
+static void
+       DYNARRAY_PREFIX##clear (struct DYNARRAY_STRUCT *list);
+#endif
+
+#if defined DYNARRAY_FINAL_TYPE
+/* Transfer the dynamic array to a permanent location at *RESULT.
+   Returns true on success on false on allocation failure.  In either
+   case, *LIST is re-initialized and can be reused.  A NULL pointer is
+   stored in *RESULT if LIST refers to an empty list.  On success, the
+   pointer in *RESULT is heap-allocated and must be deallocated using
+   free.  */
+#if 0
+static bool
+       DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *list,
+                                  DYNARRAY_FINAL_TYPE *result);
+#endif
+#else /* !defined DYNARRAY_FINAL_TYPE */
+/* Transfer the dynamic array to a heap-allocated array and return a
+   pointer to it.  The pointer is NULL if memory allocation fails, or
+   if the array is empty, so this function should be used only for
+   arrays which are known not be empty (usually because they always
+   have a sentinel at the end).  If LENGTHP is not NULL, the array
+   length is written to *LENGTHP.  *LIST is re-initialized and can be
+   reused.  */
+#if 0
+static DYNARRAY_ELEMENT *
+       DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *list,
+                                  size_t *lengthp);
+#endif
+#endif
+
+/* A minimal example which provides a growing list of integers can be
+   defined like this:
+
+     struct int_array
+     {
+       // Pointer to result array followed by its length,
+       // as required by DYNARRAY_FINAL_TYPE.
+       int *array;
+       size_t length;
+     };
+
+     #define DYNARRAY_STRUCT dynarray_int
+     #define DYNARRAY_ELEMENT int
+     #define DYNARRAY_PREFIX dynarray_int_
+     #define DYNARRAY_FINAL_TYPE struct int_array
+     #include <malloc/dynarray-skeleton.c>
+
+   To create a three-element array with elements 1, 2, 3, use this
+   code:
+
+     struct dynarray_int dyn;
+     dynarray_int_init (&dyn);
+     for (int i = 1; i <= 3; ++i)
+       {
+         int *place = dynarray_int_emplace (&dyn);
+         assert (place != NULL);
+         *place = i;
+       }
+     struct int_array result;
+     bool ok = dynarray_int_finalize (&dyn, &result);
+     assert (ok);
+     assert (result.length == 3);
+     assert (result.array[0] == 1);
+     assert (result.array[1] == 2);
+     assert (result.array[2] == 3);
+     free (result.array);
+
+   If the elements contain resources which must be freed, define
+   DYNARRAY_ELEMENT_FREE appropriately, like this:
+
+     struct str_array
+     {
+       char **array;
+       size_t length;
+     };
+
+     #define DYNARRAY_STRUCT dynarray_str
+     #define DYNARRAY_ELEMENT char *
+     #define DYNARRAY_ELEMENT_FREE(ptr) free (*ptr)
+     #define DYNARRAY_PREFIX dynarray_str_
+     #define DYNARRAY_FINAL_TYPE struct str_array
+     #include <malloc/dynarray-skeleton.c>
+ */
+
+
+/* The implementation is imported from glibc.  */
+
+/* Avoid possible conflicts with symbols exported by the GNU libc.  */
 #define __libc_dynarray_at_failure gl_dynarray_at_failure
 #define __libc_dynarray_emplace_enlarge gl_dynarray_emplace_enlarge
 #define __libc_dynarray_finalize gl_dynarray_finalize
 #define __libc_dynarray_resize_clear gl_dynarray_resize_clear
 #define __libc_dynarray_resize gl_dynarray_resize
-#include <malloc/dynarray.h>
+
+#if defined DYNARRAY_STRUCT || defined DYNARRAY_ELEMENT || defined DYNARRAY_PREFIX
+
+# include <libc-config.h>
+
+/* Define auxiliary structs and declare auxiliary functions, common to all
+   instantiations of dynarray.  */
+# include <malloc/dynarray.h>
+
+/* Define the instantiation, specified through
+     DYNARRAY_STRUCT
+     DYNARRAY_ELEMENT
+     DYNARRAY_PREFIX
+   etc.  */
+# include <malloc/dynarray-skeleton.c>
+
+#else
+
+/* This file is being included from one of the malloc/dynarray_*.c files.  */
+# include <malloc/dynarray.h>
+
+#endif
 
 #endif /* _GL_DYNARRAY_H */
diff --git a/lib/free.c b/lib/free.c
index 35872c848..b22124154 100644
--- a/lib/free.c
+++ b/lib/free.c
@@ -19,15 +19,19 @@
 
 #include <config.h>
 
+/* Specification.  */
 #include <stdlib.h>
 
-#include <errno.h>
+/* A function definition is only needed if HAVE_FREE_POSIX is not defined.  */
+#if !HAVE_FREE_POSIX
+
+# include <errno.h>
 
 void
 rpl_free (void *p)
-#undef free
+# undef free
 {
-#if defined __GNUC__ && !defined __clang__
+# if defined __GNUC__ && !defined __clang__
   /* An invalid GCC optimization
      <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98396>
      would optimize away the assignments in the code below, when link-time
@@ -39,9 +43,11 @@ rpl_free (void *p)
   errno = 0;
   free (p);
   errno = err[errno == 0];
-#else
+# else
   int err = errno;
   free (p);
   errno = err;
-#endif
+# endif
 }
+
+#endif
diff --git a/lib/intprops.h b/lib/intprops.h
index 967e32ea0..9d10028a5 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -133,7 +133,8 @@
    operators might not yield numerically correct answers due to
    arithmetic overflow.  They do not rely on undefined or
    implementation-defined behavior.  Their implementations are simple
-   and straightforward, but they are a bit harder to use than the
+   and straightforward, but they are harder to use and may be less
+   efficient than the INT_<op>_WRAPV, INT_<op>_OK, and
    INT_<op>_OVERFLOW macros described below.
 
    Example usage:
@@ -158,6 +159,9 @@
    must have minimum value MIN and maximum MAX.  Unsigned types should
    use a zero MIN of the proper type.
 
+   Because all arguments are subject to integer promotions, these
+   macros typically do not work on types narrower than 'int'.
+
    These macros are tuned for constant MIN and MAX.  For commutative
    operations such as A + B, they are also tuned for constant B.  */
 
@@ -339,9 +343,15 @@
    arguments should not have side effects.
 
    The WRAPV macros are not constant expressions.  They support only
-   +, binary -, and *.  Because the WRAPV macros convert the result,
-   they report overflow in different circumstances than the OVERFLOW
-   macros do.
+   +, binary -, and *.
+
+   Because the WRAPV macros convert the result, they report overflow
+   in different circumstances than the OVERFLOW macros do.  For
+   example, in the typical case with 16-bit 'short' and 32-bit 'int',
+   if A, B and R are all of type 'short' then INT_ADD_OVERFLOW (A, B)
+   returns false because the addition cannot overflow after A and B
+   are converted to 'int', whereas INT_ADD_WRAPV (A, B, &R) returns
+   true or false depending on whether the sum fits into 'short'.
 
    These macros are tuned for their last input argument being a constant.
 
diff --git a/lib/lc-charset-dispatch.c b/lib/lc-charset-dispatch.c
index 4b4d93ddb..98c6e9de7 100644
--- a/lib/lc-charset-dispatch.c
+++ b/lib/lc-charset-dispatch.c
@@ -26,7 +26,7 @@
 # include "localcharset.h"
 # include "streq.h"
 
-# if GNULIB_WCHAR_SINGLE
+# if GNULIB_WCHAR_SINGLE_LOCALE
 /* When we know that the locale does not change, provide a speedup by
    caching the value of locale_encoding_classification.  */
 #  define locale_encoding_classification_cached locale_encoding_classification
@@ -35,7 +35,7 @@
 #  define locale_encoding_classification_uncached locale_encoding_classification
 # endif
 
-# if GNULIB_WCHAR_SINGLE
+# if GNULIB_WCHAR_SINGLE_LOCALE
 static inline
 # endif
 enc_t
@@ -59,7 +59,7 @@ locale_encoding_classification_uncached (void)
   return enc_other;
 }
 
-# if GNULIB_WCHAR_SINGLE
+# if GNULIB_WCHAR_SINGLE_LOCALE
 
 static int cached_locale_enc = -1;
 
diff --git a/lib/libc-config.h b/lib/libc-config.h
index fcdafcb96..f14013f7e 100644
--- a/lib/libc-config.h
+++ b/lib/libc-config.h
@@ -33,9 +33,9 @@
 #include <config.h>
 
 /* On glibc this includes <features.h> and <sys/cdefs.h> and #defines
-   _FEATURES_H, __WORDSIZE, and __set_errno.  On FreeBSD 11 it
-   includes <sys/cdefs.h> which defines __nonnull.  Elsewhere it
-   is harmless.  */
+   _FEATURES_H, __WORDSIZE, and __set_errno.  On FreeBSD 11 and
+   DragonFlyBSD 5.9 it includes <sys/cdefs.h> which defines __nonnull.
+   Elsewhere it is harmless.  */
 #include <errno.h>
 
 /* From glibc <errno.h>.  */
diff --git a/lib/link.c b/lib/link.c
index 6fff67a4f..3ba897a8b 100644
--- a/lib/link.c
+++ b/lib/link.c
@@ -117,9 +117,7 @@ link (const char *file1, const char *file2)
     *p = '\0';
     if (p != dir && stat (dir, &st) != 0 && errno != EOVERFLOW)
       {
-        int saved_errno = errno;
         free (dir);
-        errno = saved_errno;
         return -1;
       }
     free (dir);
@@ -228,9 +226,7 @@ rpl_link (char const *file1, char const *file2)
           *p = '\0';
           if (stat (dir, &st) != 0 && errno != EOVERFLOW)
             {
-              int saved_errno = errno;
               free (dir);
-              errno = saved_errno;
               return -1;
             }
         }
diff --git a/lib/malloc.c b/lib/malloc.c
index 0c3e9da68..6bbb97dc2 100644
--- a/lib/malloc.c
+++ b/lib/malloc.c
@@ -30,7 +30,11 @@
 
 #include <stdlib.h>
 
-#include <errno.h>
+/* A function definition is only needed if NEED_MALLOC_GNU is defined above
+   or if the module 'malloc-posix' requests it.  */
+#if NEED_MALLOC_GNU || (GNULIB_MALLOC_POSIX && !HAVE_MALLOC_POSIX)
+
+# include <errno.h>
 
 /* Allocate an N-byte block of memory from the heap.
    If N is zero, allocate a 1-byte block.  */
@@ -40,17 +44,19 @@ rpl_malloc (size_t n)
 {
   void *result;
 
-#if NEED_MALLOC_GNU
+# if NEED_MALLOC_GNU
   if (n == 0)
     n = 1;
-#endif
+# endif
 
   result = malloc (n);
 
-#if !HAVE_MALLOC_POSIX
+# if !HAVE_MALLOC_POSIX
   if (result == NULL)
     errno = ENOMEM;
-#endif
+# endif
 
   return result;
 }
+
+#endif
diff --git a/lib/malloc/dynarray-skeleton.c b/lib/malloc/dynarray-skeleton.c
index 5b9f37bdd..48210e325 100644
--- a/lib/malloc/dynarray-skeleton.c
+++ b/lib/malloc/dynarray-skeleton.c
@@ -192,7 +192,7 @@ DYNARRAY_NAME (free__array__) (struct DYNARRAY_STRUCT *list)
 
 /* Initialize a dynamic array object.  This must be called before any
    use of the object.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static void
 DYNARRAY_NAME (init) (struct DYNARRAY_STRUCT *list)
 {
@@ -202,7 +202,7 @@ DYNARRAY_NAME (init) (struct DYNARRAY_STRUCT *list)
 }
 
 /* Deallocate the dynamic array and its elements.  */
-__attribute_maybe_unused__ __nonnull ((1))
+__attribute_maybe_unused__ __attribute_nonnull__ ((1))
 static void
 DYNARRAY_FREE (struct DYNARRAY_STRUCT *list)
 {
@@ -213,7 +213,7 @@ DYNARRAY_FREE (struct DYNARRAY_STRUCT *list)
 }
 
 /* Return true if the dynamic array is in an error state.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static inline bool
 DYNARRAY_NAME (has_failed) (const struct DYNARRAY_STRUCT *list)
 {
@@ -222,7 +222,7 @@ DYNARRAY_NAME (has_failed) (const struct DYNARRAY_STRUCT *list)
 
 /* Mark the dynamic array as failed.  All elements are deallocated as
    a side effect.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static void
 DYNARRAY_NAME (mark_failed) (struct DYNARRAY_STRUCT *list)
 {
@@ -236,7 +236,7 @@ DYNARRAY_NAME (mark_failed) (struct DYNARRAY_STRUCT *list)
 
 /* Return the number of elements which have been added to the dynamic
    array.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static inline size_t
 DYNARRAY_NAME (size) (const struct DYNARRAY_STRUCT *list)
 {
@@ -245,7 +245,7 @@ DYNARRAY_NAME (size) (const struct DYNARRAY_STRUCT *list)
 
 /* Return a pointer to the array element at INDEX.  Terminate the
    process if INDEX is out of bounds.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static inline DYNARRAY_ELEMENT *
 DYNARRAY_NAME (at) (struct DYNARRAY_STRUCT *list, size_t index)
 {
@@ -257,7 +257,7 @@ DYNARRAY_NAME (at) (struct DYNARRAY_STRUCT *list, size_t index)
 /* Return a pointer to the first array element, if any.  For a
    zero-length array, the pointer can be NULL even though the dynamic
    array has not entered the failure state.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static inline DYNARRAY_ELEMENT *
 DYNARRAY_NAME (begin) (struct DYNARRAY_STRUCT *list)
 {
@@ -267,7 +267,7 @@ DYNARRAY_NAME (begin) (struct DYNARRAY_STRUCT *list)
 /* Return a pointer one element past the last array element.  For a
    zero-length array, the pointer can be NULL even though the dynamic
    array has not entered the failure state.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static inline DYNARRAY_ELEMENT *
 DYNARRAY_NAME (end) (struct DYNARRAY_STRUCT *list)
 {
@@ -294,7 +294,7 @@ DYNARRAY_NAME (add__) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item)
 /* Add ITEM at the end of the array, enlarging it by one element.
    Mark *LIST as failed if the dynamic array allocation size cannot be
    increased.  */
-__nonnull ((1))
+__attribute_nonnull__ ((1))
 static inline void
 DYNARRAY_NAME (add) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item)
 {
@@ -348,7 +348,8 @@ DYNARRAY_NAME (emplace__) (struct DYNARRAY_STRUCT *list)
 /* Allocate a place for a new element in *LIST and return a pointer to
    it.  The pointer can be NULL if the dynamic array cannot be
    enlarged due to a memory allocation failure.  */
-__attribute_maybe_unused__ __attribute_warn_unused_result__ __nonnull ((1))
+__attribute_maybe_unused__ __attribute_warn_unused_result__
+__attribute_nonnull__ ((1))
 static
 /* Avoid inlining with the larger initialization code.  */
 #if !(defined (DYNARRAY_ELEMENT_INIT) || defined (DYNARRAY_ELEMENT_FREE))
@@ -372,7 +373,7 @@ DYNARRAY_NAME (emplace) (struct DYNARRAY_STRUCT *list)
    existing size, new elements are added (which can be initialized).
    Otherwise, the list is truncated, and elements are freed.  Return
    false on memory allocation failure (and mark *LIST as failed).  */
-__attribute_maybe_unused__ __nonnull ((1))
+__attribute_maybe_unused__ __attribute_nonnull__ ((1))
 static bool
 DYNARRAY_NAME (resize) (struct DYNARRAY_STRUCT *list, size_t size)
 {
@@ -417,7 +418,7 @@ DYNARRAY_NAME (resize) (struct DYNARRAY_STRUCT *list, size_t size)
 }
 
 /* Remove the last element of LIST if it is present.  */
-__attribute_maybe_unused__ __nonnull ((1))
+__attribute_maybe_unused__ __attribute_nonnull__ ((1))
 static void
 DYNARRAY_NAME (remove_last) (struct DYNARRAY_STRUCT *list)
 {
@@ -434,7 +435,7 @@ DYNARRAY_NAME (remove_last) (struct DYNARRAY_STRUCT *list)
 
 /* Remove all elements from the list.  The elements are freed, but the
    list itself is not.  */
-__attribute_maybe_unused__ __nonnull ((1))
+__attribute_maybe_unused__ __attribute_nonnull__ ((1))
 static void
 DYNARRAY_NAME (clear) (struct DYNARRAY_STRUCT *list)
 {
@@ -452,7 +453,8 @@ DYNARRAY_NAME (clear) (struct DYNARRAY_STRUCT *list)
    stored in *RESULT if LIST refers to an empty list.  On success, the
    pointer in *RESULT is heap-allocated and must be deallocated using
    free.  */
-__attribute_maybe_unused__ __attribute_warn_unused_result__ __nonnull ((1, 2))
+__attribute_maybe_unused__ __attribute_warn_unused_result__
+__attribute_nonnull__ ((1, 2))
 static bool
 DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list,
                           DYNARRAY_FINAL_TYPE *result)
@@ -483,7 +485,8 @@ DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list,
    have a sentinel at the end).  If LENGTHP is not NULL, the array
    length is written to *LENGTHP.  *LIST is re-initialized and can be
    reused.  */
-__attribute_maybe_unused__ __attribute_warn_unused_result__ __nonnull ((1))
+__attribute_maybe_unused__ __attribute_warn_unused_result__
+__attribute_nonnull__ ((1))
 static DYNARRAY_ELEMENT *
 DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list, size_t *lengthp)
 {
diff --git a/lib/malloc/dynarray_at_failure.c b/lib/malloc/dynarray_at_failure.c
index 0fa12c7cd..4f840db7c 100644
--- a/lib/malloc/dynarray_at_failure.c
+++ b/lib/malloc/dynarray_at_failure.c
@@ -16,6 +16,10 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <dynarray.h>
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/lib/malloc/dynarray_emplace_enlarge.c b/lib/malloc/dynarray_emplace_enlarge.c
index ddfe306fc..0f8baf94a 100644
--- a/lib/malloc/dynarray_emplace_enlarge.c
+++ b/lib/malloc/dynarray_emplace_enlarge.c
@@ -16,6 +16,10 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <dynarray.h>
 #include <errno.h>
 #include <intprops.h>
diff --git a/lib/malloc/dynarray_finalize.c b/lib/malloc/dynarray_finalize.c
index 8ec6ad2bc..c33da4138 100644
--- a/lib/malloc/dynarray_finalize.c
+++ b/lib/malloc/dynarray_finalize.c
@@ -16,6 +16,10 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <dynarray.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/lib/malloc/dynarray_resize.c b/lib/malloc/dynarray_resize.c
index 5c60927f3..5a57166a8 100644
--- a/lib/malloc/dynarray_resize.c
+++ b/lib/malloc/dynarray_resize.c
@@ -16,6 +16,10 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <dynarray.h>
 #include <errno.h>
 #include <intprops.h>
diff --git a/lib/malloc/dynarray_resize_clear.c b/lib/malloc/dynarray_resize_clear.c
index e893d1d58..9c43b00c3 100644
--- a/lib/malloc/dynarray_resize_clear.c
+++ b/lib/malloc/dynarray_resize_clear.c
@@ -16,6 +16,10 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#ifndef _LIBC
+# include <libc-config.h>
+#endif
+
 #include <dynarray.h>
 #include <string.h>
 
diff --git a/lib/malloca.h b/lib/malloca.h
index fd40073e3..9cf7fbb52 100644
--- a/lib/malloca.h
+++ b/lib/malloca.h
@@ -77,6 +77,7 @@ extern void freea (void *p);
 /* nmalloca(N,S) is an overflow-safe variant of malloca (N * S).
    It allocates an array of N objects, each with S bytes of memory,
    on the stack.  S must be positive and N must be nonnegative.
+   Either N or S should be of type ptrdiff_t or size_t or wider.
    The array must be freed using freea() before the function returns.  */
 #define nmalloca(n, s) (xalloc_oversized (n, s) ? NULL : malloca ((n) * (s)))
 
diff --git a/lib/math.in.h b/lib/math.in.h
index 73b13fa17..d80047cd6 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -2579,7 +2579,7 @@ _GL_EXTERN_C int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST;
 #  if defined isnan || defined GNULIB_NAMESPACE
 _GL_MATH_CXX_REAL_FLOATING_DECL_1 (isnan)
 #   undef isnan
-#   if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || (defined __FreeBSD__ && __clang_major__ < 7) || defined __OpenBSD__ || (defined _WIN32 && !defined __CYGWIN__)))
+#   if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__ && __clang_major__ < 12) || (defined __FreeBSD__ && __clang_major__ < 7) || defined __OpenBSD__ || (defined _WIN32 && !defined __CYGWIN__)))
   /* This platform's <cmath> possibly defines isnan through a set of inline
      functions.  */
 _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isnan, rpl_isnan, bool)
diff --git a/lib/mbrtowc-impl-utf8.h b/lib/mbrtowc-impl-utf8.h
index b27516bc9..ea5ef1fe5 100644
--- a/lib/mbrtowc-impl-utf8.h
+++ b/lib/mbrtowc-impl-utf8.h
@@ -96,7 +96,7 @@
 
                     if ((c2 ^ 0x80) < 0x40
                         && (c >= 0xf1 || c2 >= 0x90)
-                        && (c < 0xf4 || (c == 0xf4 && c2 < 0x90)))
+                        && (c < 0xf4 || (/* c == 0xf4 && */ c2 < 0x90)))
                       {
                         if (m == 2)
                           goto incomplete;
diff --git a/lib/mbtowc-lock.h b/lib/mbtowc-lock.h
index 320613eae..093951713 100644
--- a/lib/mbtowc-lock.h
+++ b/lib/mbtowc-lock.h
@@ -32,7 +32,17 @@ mbtowc_unlocked (wchar_t *pwc, const char *p, size_t m)
 /* Prohibit renaming this symbol.  */
 #undef gl_get_mbtowc_lock
 
-#if defined _WIN32 && !defined __CYGWIN__
+#if GNULIB_MBRTOWC_SINGLE_THREAD
+
+/* All uses of this function are in a single thread.  No locking needed.  */
+
+static int
+mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
+{
+  return mbtowc_unlocked (pwc, p, m);
+}
+
+#elif defined _WIN32 && !defined __CYGWIN__
 
 extern __declspec(dllimport) CRITICAL_SECTION *gl_get_mbtowc_lock (void);
 
diff --git a/lib/mempcpy.c b/lib/mempcpy.c
index 39e476dae..c80e119f7 100644
--- a/lib/mempcpy.c
+++ b/lib/mempcpy.c
@@ -19,6 +19,9 @@
 /* Specification.  */
 #include <string.h>
 
+/* A function definition is only needed if HAVE_MEMPCPY is not defined.  */
+#if !HAVE_MEMPCPY
+
 /* Copy N bytes of SRC to DEST, return pointer to bytes after the
    last written byte.  */
 void *
@@ -26,3 +29,5 @@ mempcpy (void *dest, const void *src, size_t n)
 {
   return (char *) memcpy (dest, src, n) + n;
 }
+
+#endif
diff --git a/lib/putenv.c b/lib/putenv.c
index 665efffa0..d342b8153 100644
--- a/lib/putenv.c
+++ b/lib/putenv.c
@@ -82,15 +82,13 @@ _unsetenv (const char *name)
 
 #if HAVE_DECL__PUTENV
   {
-    int putenv_result, putenv_errno;
+    int putenv_result;
     char *name_ = malloc (len + 2);
     memcpy (name_, name, len);
     name_[len] = '=';
     name_[len + 1] = 0;
     putenv_result = _putenv (name_);
-    putenv_errno = errno;
     free (name_);
-    __set_errno (putenv_errno);
     return putenv_result;
   }
 #else
@@ -144,7 +142,7 @@ putenv (char *string)
       /* _putenv ("NAME=") unsets NAME, so invoke _putenv ("NAME= ")
          to allocate the environ vector and then replace the new
          entry with "NAME=".  */
-      int putenv_result, putenv_errno;
+      int putenv_result;
       char *name_x = malloc (name_end - string + sizeof "= ");
       if (!name_x)
         return -1;
@@ -152,7 +150,6 @@ putenv (char *string)
       name_x[name_end - string + 1] = ' ';
       name_x[name_end - string + 2] = 0;
       putenv_result = _putenv (name_x);
-      putenv_errno = errno;
       for (ep = environ; *ep; ep++)
         if (strcmp (*ep, name_x) == 0)
           {
@@ -166,11 +163,10 @@ putenv (char *string)
              fix that by calling SetEnvironmentVariable directly.  */
           name_x[name_end - string] = 0;
           putenv_result = SetEnvironmentVariable (name_x, "") ? 0 : -1;
-          putenv_errno = ENOMEM; /* ENOMEM is the only way to fail.  */
+          errno = ENOMEM; /* ENOMEM is the only way to fail.  */
         }
 # endif
       free (name_x);
-      __set_errno (putenv_errno);
       return putenv_result;
     }
 #else
diff --git a/lib/rawmemchr.c b/lib/rawmemchr.c
index 655cc8ec9..ef356895e 100644
--- a/lib/rawmemchr.c
+++ b/lib/rawmemchr.c
@@ -19,6 +19,9 @@
 /* Specification.  */
 #include <string.h>
 
+/* A function definition is only needed if HAVE_RAWMEMCHR is not defined.  */
+#if !HAVE_RAWMEMCHR
+
 /* Find the first occurrence of C in S.  */
 void *
 rawmemchr (const void *s, int c_in)
@@ -134,3 +137,5 @@ rawmemchr (const void *s, int c_in)
     char_ptr++;
   return (void *) char_ptr;
 }
+
+#endif
diff --git a/lib/realloc.c b/lib/realloc.c
new file mode 100644
index 000000000..114551498
--- /dev/null
+++ b/lib/realloc.c
@@ -0,0 +1,85 @@
+/* realloc() function that is glibc compatible.
+
+   Copyright (C) 1997, 2003-2004, 2006-2007, 2009-2021 Free Software
+   Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* written by Jim Meyering and Bruno Haible */
+
+#define _GL_USE_STDLIB_ALLOC 1
+#include <config.h>
+
+/* Only the AC_FUNC_REALLOC macro defines 'realloc' already in config.h.  */
+#ifdef realloc
+# define NEED_REALLOC_GNU 1
+/* Whereas the gnulib module 'realloc-gnu' defines HAVE_REALLOC_GNU.  */
+#elif GNULIB_REALLOC_GNU && !HAVE_REALLOC_GNU
+# define NEED_REALLOC_GNU 1
+#endif
+
+/* Infer the properties of the system's malloc function.
+   The gnulib module 'malloc-gnu' defines HAVE_MALLOC_GNU.  */
+#if GNULIB_MALLOC_GNU && HAVE_MALLOC_GNU
+# define SYSTEM_MALLOC_GLIBC_COMPATIBLE 1
+#endif
+
+#include <stdlib.h>
+
+/* A function definition is only needed if NEED_REALLOC_GNU is defined above
+   or if the module 'realloc-posix' requests it.  */
+#if NEED_REALLOC_GNU || (GNULIB_REALLOC_POSIX && !HAVE_REALLOC_POSIX)
+
+# include <errno.h>
+
+/* Change the size of an allocated block of memory P to N bytes,
+   with error checking.  If N is zero, change it to 1.  If P is NULL,
+   use malloc.  */
+
+void *
+rpl_realloc (void *p, size_t n)
+{
+  void *result;
+
+# if NEED_REALLOC_GNU
+  if (n == 0)
+    {
+      n = 1;
+
+      /* In theory realloc might fail, so don't rely on it to free.  */
+      free (p);
+      p = NULL;
+    }
+# endif
+
+  if (p == NULL)
+    {
+# if GNULIB_REALLOC_GNU && !NEED_REALLOC_GNU && !SYSTEM_MALLOC_GLIBC_COMPATIBLE
+      if (n == 0)
+        n = 1;
+# endif
+      result = malloc (n);
+    }
+  else
+    result = realloc (p, n);
+
+# if !HAVE_REALLOC_POSIX
+  if (result == NULL)
+    errno = ENOMEM;
+# endif
+
+  return result;
+}
+
+#endif
diff --git a/lib/regcomp.c b/lib/regcomp.c
index d93698ae7..887e5b506 100644
--- a/lib/regcomp.c
+++ b/lib/regcomp.c
@@ -1695,12 +1695,14 @@ calc_eclosure_iter (re_node_set *new_set, re_dfa_t *dfa, Idx node, bool root)
   reg_errcode_t err;
   Idx i;
   re_node_set eclosure;
-  bool ok;
   bool incomplete = false;
   err = re_node_set_alloc (&eclosure, dfa->edests[node].nelem + 1);
   if (__glibc_unlikely (err != REG_NOERROR))
     return err;
 
+  /* An epsilon closure includes itself.  */
+  eclosure.elems[eclosure.nelem++] = node;
+
   /* This indicates that we are calculating this node now.
      We reference this value to avoid infinite loop.  */
   dfa->eclosures[node].nelem = -1;
@@ -1753,10 +1755,6 @@ calc_eclosure_iter (re_node_set *new_set, re_dfa_t *dfa, Idx node, bool root)
 	  }
       }
 
-  /* An epsilon closure includes itself.  */
-  ok = re_node_set_insert (&eclosure, node);
-  if (__glibc_unlikely (! ok))
-    return REG_ESPACE;
   if (incomplete && !root)
     dfa->eclosures[node].nelem = 0;
   else
diff --git a/lib/regex_internal.c b/lib/regex_internal.c
index 9dd387ef8..55f6b66de 100644
--- a/lib/regex_internal.c
+++ b/lib/regex_internal.c
@@ -1314,6 +1314,7 @@ re_node_set_insert (re_node_set *set, Idx elem)
     {
       for (idx = set->nelem; set->elems[idx - 1] > elem; idx--)
 	set->elems[idx] = set->elems[idx - 1];
+      DEBUG_ASSERT (set->elems[idx - 1] < elem);
     }
 
   /* Insert the new element.  */
diff --git a/lib/regex_internal.h b/lib/regex_internal.h
index b4f91d9ec..1245e782f 100644
--- a/lib/regex_internal.h
+++ b/lib/regex_internal.h
@@ -32,7 +32,10 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-#include <dynarray.h>
+#ifndef _LIBC
+# include <dynarray.h>
+#endif
+
 #include <intprops.h>
 #include <verify.h>
 
@@ -50,14 +53,14 @@
 # define lock_fini(lock) ((void) 0)
 # define lock_lock(lock) __libc_lock_lock (lock)
 # define lock_unlock(lock) __libc_lock_unlock (lock)
-#elif defined GNULIB_LOCK && !defined USE_UNLOCKED_IO
+#elif defined GNULIB_LOCK && !defined GNULIB_REGEX_SINGLE_THREAD
 # include "glthread/lock.h"
 # define lock_define(name) gl_lock_define (, name)
 # define lock_init(lock) glthread_lock_init (&(lock))
 # define lock_fini(lock) glthread_lock_destroy (&(lock))
 # define lock_lock(lock) glthread_lock_lock (&(lock))
 # define lock_unlock(lock) glthread_lock_unlock (&(lock))
-#elif defined GNULIB_PTHREAD && !defined USE_UNLOCKED_IO
+#elif defined GNULIB_PTHREAD && !defined GNULIB_REGEX_SINGLE_THREAD
 # include <pthread.h>
 # define lock_define(name) pthread_mutex_t name;
 # define lock_init(lock) pthread_mutex_init (&(lock), 0)
@@ -830,12 +833,14 @@ re_string_elem_size_at (const re_string_t *pstr, Idx idx)
 }
 #endif /* RE_ENABLE_I18N */
 
-#ifndef FALLTHROUGH
-# if (__GNUC__ >= 7) || (__clang_major__ >= 10)
+#ifdef _LIBC
+# if __GNUC__ >= 7
 #  define FALLTHROUGH __attribute__ ((__fallthrough__))
 # else
 #  define FALLTHROUGH ((void) 0)
 # endif
+#else
+# include "attribute.h"
 #endif
 
 #endif /*  _REGEX_INTERNAL_H */
diff --git a/lib/regexec.c b/lib/regexec.c
index f7b4f9cfc..6309deac8 100644
--- a/lib/regexec.c
+++ b/lib/regexec.c
@@ -59,7 +59,7 @@ static void update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
 			 Idx cur_idx, Idx nmatch);
 static reg_errcode_t push_fail_stack (struct re_fail_stack_t *fs,
 				      Idx str_idx, Idx dest_node, Idx nregs,
-				      regmatch_t *regs,
+				      regmatch_t *regs, regmatch_t *prevregs,
 				      re_node_set *eps_via_nodes);
 static reg_errcode_t set_regs (const regex_t *preg,
 			       const re_match_context_t *mctx,
@@ -186,7 +186,8 @@ static reg_errcode_t extend_buffers (re_match_context_t *mctx, int min_len);
    REG_NOTBOL is set, then ^ does not match at the beginning of the
    string; if REG_NOTEOL is set, then $ does not match at the end.
 
-   We return 0 if we find a match and REG_NOMATCH if not.  */
+   Return 0 if a match is found, REG_NOMATCH if not, REG_BADPAT if
+   EFLAGS is invalid.  */
 
 int
 regexec (const regex_t *__restrict preg, const char *__restrict string,
@@ -269,8 +270,8 @@ compat_symbol (libc, __compat_regexec, regexec, GLIBC_2_0);
    strings.)
 
    On success, re_match* functions return the length of the match, re_search*
-   return the position of the start of the match.  Return value -1 means no
-   match was found and -2 indicates an internal error.  */
+   return the position of the start of the match.  They return -1 on
+   match failure, -2 on error.  */
 
 regoff_t
 re_match (struct re_pattern_buffer *bufp, const char *string, Idx length,
@@ -1206,27 +1207,26 @@ check_halt_state_context (const re_match_context_t *mctx,
 /* Compute the next node to which "NFA" transit from NODE("NFA" is a NFA
    corresponding to the DFA).
    Return the destination node, and update EPS_VIA_NODES;
-   return -1 in case of errors.  */
+   return -1 on match failure, -2 on error.  */
 
 static Idx
 proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
+		   regmatch_t *prevregs,
 		   Idx *pidx, Idx node, re_node_set *eps_via_nodes,
 		   struct re_fail_stack_t *fs)
 {
   const re_dfa_t *const dfa = mctx->dfa;
-  Idx i;
-  bool ok;
   if (IS_EPSILON_NODE (dfa->nodes[node].type))
     {
       re_node_set *cur_nodes = &mctx->state_log[*pidx]->nodes;
       re_node_set *edests = &dfa->edests[node];
-      Idx dest_node;
-      ok = re_node_set_insert (eps_via_nodes, node);
+      bool ok = re_node_set_insert (eps_via_nodes, node);
       if (__glibc_unlikely (! ok))
 	return -2;
-      /* Pick up a valid destination, or return -1 if none
-	 is found.  */
-      for (dest_node = -1, i = 0; i < edests->nelem; ++i)
+
+      /* Pick a valid destination, or return -1 if none is found.  */
+      Idx dest_node = -1;
+      for (Idx i = 0; i < edests->nelem; i++)
 	{
 	  Idx candidate = edests->elems[i];
 	  if (!re_node_set_contains (cur_nodes, candidate))
@@ -1244,7 +1244,7 @@ proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
 	      /* Otherwise, push the second epsilon-transition on the fail stack.  */
 	      else if (fs != NULL
 		       && push_fail_stack (fs, *pidx, candidate, nregs, regs,
-					   eps_via_nodes))
+					   prevregs, eps_via_nodes))
 		return -2;
 
 	      /* We know we are going to exit.  */
@@ -1288,7 +1288,7 @@ proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
 	  if (naccepted == 0)
 	    {
 	      Idx dest_node;
-	      ok = re_node_set_insert (eps_via_nodes, node);
+	      bool ok = re_node_set_insert (eps_via_nodes, node);
 	      if (__glibc_unlikely (! ok))
 		return -2;
 	      dest_node = dfa->edests[node].elems[0];
@@ -1317,7 +1317,8 @@ proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
 static reg_errcode_t
 __attribute_warn_unused_result__
 push_fail_stack (struct re_fail_stack_t *fs, Idx str_idx, Idx dest_node,
-		 Idx nregs, regmatch_t *regs, re_node_set *eps_via_nodes)
+		 Idx nregs, regmatch_t *regs, regmatch_t *prevregs,
+		 re_node_set *eps_via_nodes)
 {
   reg_errcode_t err;
   Idx num = fs->num++;
@@ -1333,25 +1334,30 @@ push_fail_stack (struct re_fail_stack_t *fs, Idx str_idx, Idx dest_node,
     }
   fs->stack[num].idx = str_idx;
   fs->stack[num].node = dest_node;
-  fs->stack[num].regs = re_malloc (regmatch_t, nregs);
+  fs->stack[num].regs = re_malloc (regmatch_t, 2 * nregs);
   if (fs->stack[num].regs == NULL)
     return REG_ESPACE;
   memcpy (fs->stack[num].regs, regs, sizeof (regmatch_t) * nregs);
+  memcpy (fs->stack[num].regs + nregs, prevregs, sizeof (regmatch_t) * nregs);
   err = re_node_set_init_copy (&fs->stack[num].eps_via_nodes, eps_via_nodes);
   return err;
 }
 
 static Idx
 pop_fail_stack (struct re_fail_stack_t *fs, Idx *pidx, Idx nregs,
-		regmatch_t *regs, re_node_set *eps_via_nodes)
+		regmatch_t *regs, regmatch_t *prevregs,
+		re_node_set *eps_via_nodes)
 {
+  if (fs == NULL || fs->num == 0)
+    return -1;
   Idx num = --fs->num;
-  DEBUG_ASSERT (num >= 0);
   *pidx = fs->stack[num].idx;
   memcpy (regs, fs->stack[num].regs, sizeof (regmatch_t) * nregs);
+  memcpy (prevregs, fs->stack[num].regs + nregs, sizeof (regmatch_t) * nregs);
   re_node_set_free (eps_via_nodes);
   re_free (fs->stack[num].regs);
   *eps_via_nodes = fs->stack[num].eps_via_nodes;
+  DEBUG_ASSERT (0 <= fs->stack[num].node);
   return fs->stack[num].node;
 }
 
@@ -1407,33 +1413,32 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
     {
       update_regs (dfa, pmatch, prev_idx_match, cur_node, idx, nmatch);
 
-      if (idx == pmatch[0].rm_eo && cur_node == mctx->last_node)
+      if ((idx == pmatch[0].rm_eo && cur_node == mctx->last_node)
+	  || re_node_set_contains (&eps_via_nodes, cur_node))
 	{
 	  Idx reg_idx;
+	  cur_node = -1;
 	  if (fs)
 	    {
 	      for (reg_idx = 0; reg_idx < nmatch; ++reg_idx)
 		if (pmatch[reg_idx].rm_so > -1 && pmatch[reg_idx].rm_eo == -1)
-		  break;
-	      if (reg_idx == nmatch)
-		{
-		  re_node_set_free (&eps_via_nodes);
-		  regmatch_list_free (&prev_match);
-		  return free_fail_stack_return (fs);
-		}
-	      cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
-					 &eps_via_nodes);
+		  {
+		    cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
+					       prev_idx_match, &eps_via_nodes);
+		    break;
+		  }
 	    }
-	  else
+	  if (cur_node < 0)
 	    {
 	      re_node_set_free (&eps_via_nodes);
 	      regmatch_list_free (&prev_match);
-	      return REG_NOERROR;
+	      return free_fail_stack_return (fs);
 	    }
 	}
 
       /* Proceed to next node.  */
-      cur_node = proceed_next_node (mctx, nmatch, pmatch, &idx, cur_node,
+      cur_node = proceed_next_node (mctx, nmatch, pmatch, prev_idx_match,
+				    &idx, cur_node,
 				    &eps_via_nodes, fs);
 
       if (__glibc_unlikely (cur_node < 0))
@@ -1445,13 +1450,13 @@ set_regs (const regex_t *preg, const re_match_context_t *mctx, size_t nmatch,
 	      free_fail_stack_return (fs);
 	      return REG_ESPACE;
 	    }
-	  if (fs)
-	    cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
-				       &eps_via_nodes);
-	  else
+	  cur_node = pop_fail_stack (fs, &idx, nmatch, pmatch,
+				     prev_idx_match, &eps_via_nodes);
+	  if (cur_node < 0)
 	    {
 	      re_node_set_free (&eps_via_nodes);
 	      regmatch_list_free (&prev_match);
+	      free_fail_stack_return (fs);
 	      return REG_NOMATCH;
 	    }
 	}
@@ -1495,10 +1500,10 @@ update_regs (const re_dfa_t *dfa, regmatch_t *pmatch,
     }
   else if (type == OP_CLOSE_SUBEXP)
     {
+      /* We are at the last node of this sub expression.  */
       Idx reg_num = dfa->nodes[cur_node].opr.idx + 1;
       if (reg_num < nmatch)
 	{
-	  /* We are at the last node of this sub expression.  */
 	  if (pmatch[reg_num].rm_so < cur_idx)
 	    {
 	      pmatch[reg_num].rm_eo = cur_idx;
@@ -2195,6 +2200,7 @@ sift_states_iter_mb (const re_match_context_t *mctx, re_sift_context_t *sctx,
 
 /* Return the next state to which the current state STATE will transit by
    accepting the current input byte, and update STATE_LOG if necessary.
+   Return NULL on failure.
    If STATE can accept a multibyte char/collating element/back reference
    update the destination of STATE_LOG.  */
 
@@ -2395,7 +2401,7 @@ check_subexp_matching_top (re_match_context_t *mctx, re_node_set *cur_nodes,
 
 #if 0
 /* Return the next state to which the current state STATE will transit by
-   accepting the current input byte.  */
+   accepting the current input byte.  Return NULL on failure.  */
 
 static re_dfastate_t *
 transit_state_sb (reg_errcode_t *err, re_match_context_t *mctx,
@@ -2817,7 +2823,8 @@ find_subexp_node (const re_dfa_t *dfa, const re_node_set *nodes,
 /* Check whether the node TOP_NODE at TOP_STR can arrive to the node
    LAST_NODE at LAST_STR.  We record the path onto PATH since it will be
    heavily reused.
-   Return REG_NOERROR if it can arrive, or REG_NOMATCH otherwise.  */
+   Return REG_NOERROR if it can arrive, REG_NOMATCH if it cannot,
+   REG_ESPACE if memory is exhausted.  */
 
 static reg_errcode_t
 __attribute_warn_unused_result__
@@ -3433,7 +3440,8 @@ build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
 /* Group all nodes belonging to STATE into several destinations.
    Then for all destinations, set the nodes belonging to the destination
    to DESTS_NODE[i] and set the characters accepted by the destination
-   to DEST_CH[i].  This function return the number of destinations.  */
+   to DEST_CH[i].  Return the number of destinations if successful,
+   -1 on internal error.  */
 
 static Idx
 group_nodes_into_DFAstates (const re_dfa_t *dfa, const re_dfastate_t *state,
@@ -4211,7 +4219,8 @@ match_ctx_add_subtop (re_match_context_t *mctx, Idx node, Idx str_idx)
 }
 
 /* Register the node NODE, whose type is OP_CLOSE_SUBEXP, and which matches
-   at STR_IDX, whose corresponding OP_OPEN_SUBEXP is SUB_TOP.  */
+   at STR_IDX, whose corresponding OP_OPEN_SUBEXP is SUB_TOP.
+   Return the new entry if successful, NULL if memory is exhausted.  */
 
 static re_sub_match_last_t *
 match_ctx_add_sublast (re_sub_match_top_t *subtop, Idx node, Idx str_idx)
diff --git a/lib/rename.c b/lib/rename.c
index 0d9f2039c..487302543 100644
--- a/lib/rename.c
+++ b/lib/rename.c
@@ -165,10 +165,8 @@ rpl_rename (char const *src, char const *dst)
         }
       if (rmdir (dst))
         {
-          error = errno;
           free (src_temp);
           free (dst_temp);
-          errno = error;
           return -1;
         }
       free (src_temp);
diff --git a/lib/scratch_buffer.h b/lib/scratch_buffer.h
index 5b8f61706..4b17f72ea 100644
--- a/lib/scratch_buffer.h
+++ b/lib/scratch_buffer.h
@@ -19,12 +19,105 @@
 #ifndef _GL_SCRATCH_BUFFER_H
 #define _GL_SCRATCH_BUFFER_H
 
+/* Scratch buffers with a default stack allocation and fallback to
+   heap allocation.  It is expected that this function is used in this
+   way:
+
+     struct scratch_buffer tmpbuf;
+     scratch_buffer_init (&tmpbuf);
+
+     while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length))
+       if (!scratch_buffer_grow (&tmpbuf))
+         return -1;
+
+     scratch_buffer_free (&tmpbuf);
+     return 0;
+
+   The allocation functions (scratch_buffer_grow,
+   scratch_buffer_grow_preserve, scratch_buffer_set_array_size) make
+   sure that the heap allocation, if any, is freed, so that the code
+   above does not have a memory leak.  The buffer still remains in a
+   state that can be deallocated using scratch_buffer_free, so a loop
+   like this is valid as well:
+
+     struct scratch_buffer tmpbuf;
+     scratch_buffer_init (&tmpbuf);
+
+     while (!function_that_uses_buffer (tmpbuf.data, tmpbuf.length))
+       if (!scratch_buffer_grow (&tmpbuf))
+         break;
+
+     scratch_buffer_free (&tmpbuf);
+
+   scratch_buffer_grow and scratch_buffer_grow_preserve are guaranteed
+   to grow the buffer by at least 512 bytes.  This means that when
+   using the scratch buffer as a backing store for a non-character
+   array whose element size, in bytes, is 512 or smaller, the scratch
+   buffer only has to grow once to make room for at least one more
+   element.
+*/
+
+/* Scratch buffer.  Must be initialized with scratch_buffer_init
+   before its use.  */
+struct scratch_buffer;
+
+/* Initializes *BUFFER so that BUFFER->data points to BUFFER->__space
+   and BUFFER->length reflects the available space.  */
+#if 0
+extern void scratch_buffer_init (struct scratch_buffer *buffer);
+#endif
+
+/* Deallocates *BUFFER (if it was heap-allocated).  */
+#if 0
+extern void scratch_buffer_free (struct scratch_buffer *buffer);
+#endif
+
+/* Grow *BUFFER by some arbitrary amount.  The buffer contents is NOT
+   preserved.  Return true on success, false on allocation failure (in
+   which case the old buffer is freed).  On success, the new buffer is
+   larger than the previous size.  On failure, *BUFFER is deallocated,
+   but remains in a free-able state, and errno is set.  */
+#if 0
+extern bool scratch_buffer_grow (struct scratch_buffer *buffer);
+#endif
+
+/* Like scratch_buffer_grow, but preserve the old buffer
+   contents on success, as a prefix of the new buffer.  */
+#if 0
+extern bool scratch_buffer_grow_preserve (struct scratch_buffer *buffer);
+#endif
+
+/* Grow *BUFFER so that it can store at least NELEM elements of SIZE
+   bytes.  The buffer contents are NOT preserved.  Both NELEM and SIZE
+   can be zero.  Return true on success, false on allocation failure
+   (in which case the old buffer is freed, but *BUFFER remains in a
+   free-able state, and errno is set).  It is unspecified whether this
+   function can reduce the array size.  */
+#if 0
+extern bool scratch_buffer_set_array_size (struct scratch_buffer *buffer,
+                                           size_t nelem, size_t size);
+#endif
+
+/* Return a copy of *BUFFER's first SIZE bytes as a heap-allocated block,
+   deallocating *BUFFER if it was heap-allocated.  SIZE must be at
+   most *BUFFER's size.  Return NULL (setting errno) on memory
+   exhaustion.  */
+#if 0
+extern void *scratch_buffer_dupfree (struct scratch_buffer *buffer,
+                                     size_t size);
+#endif
+
+
+/* The implementation is imported from glibc.  */
+
 #include <libc-config.h>
 
+/* Avoid possible conflicts with symbols exported by the GNU libc.  */
 #define __libc_scratch_buffer_dupfree gl_scratch_buffer_dupfree
 #define __libc_scratch_buffer_grow gl_scratch_buffer_grow
 #define __libc_scratch_buffer_grow_preserve gl_scratch_buffer_grow_preserve
 #define __libc_scratch_buffer_set_array_size gl_scratch_buffer_set_array_size
+
 #include <malloc/scratch_buffer.h>
 
 #endif /* _GL_SCRATCH_BUFFER_H */
diff --git a/lib/stdalign.in.h b/lib/stdalign.in.h
index 597293db8..7b51043ec 100644
--- a/lib/stdalign.in.h
+++ b/lib/stdalign.in.h
@@ -104,12 +104,13 @@
 #if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
 # if defined __cplusplus && 201103 <= __cplusplus
 #  define _Alignas(a) alignas (a)
-# elif ((defined __APPLE__ && defined __MACH__                  \
-         ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__)                 \
-         : __GNUC__ && !defined __ibmxl__)                      \
-        || (4 <= __clang_major__)                               \
-        || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC))  \
-        || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__)
+# elif (!defined __attribute__ \
+        && ((defined __APPLE__ && defined __MACH__ \
+             ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+             : __GNUC__ && !defined __ibmxl__) \
+            || (4 <= __clang_major__) \
+            || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC)) \
+            || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__))
 #  define _Alignas(a) __attribute__ ((__aligned__ (a)))
 # elif 1300 <= _MSC_VER
 #  define _Alignas(a) __declspec (align (a))
diff --git a/lib/stddef.in.h b/lib/stddef.in.h
index b4f617298..4c53e6455 100644
--- a/lib/stddef.in.h
+++ b/lib/stddef.in.h
@@ -42,6 +42,13 @@
 #   define _GL_STDDEF_WINT_T
 #  endif
 #  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
+   /* On TinyCC, make sure that the macros that indicate the special invocation
+      convention get undefined.  */
+#  undef __need_wchar_t
+#  undef __need_size_t
+#  undef __need_ptrdiff_t
+#  undef __need_NULL
+#  undef __need_wint_t
 # endif
 
 #else
@@ -51,7 +58,7 @@
 
 /* On AIX 7.2, with xlc in 64-bit mode, <stddef.h> defines max_align_t to a
    type with alignment 4, but 'long' has alignment 8.  */
-#  if defined _AIX && defined _ARCH_PPC64
+#  if defined _AIX && defined __LP64__
 #   if !GNULIB_defined_max_align_t
 #    ifdef _MAX_ALIGN_T
 /* /usr/include/stddef.h has already defined max_align_t.  Override it.  */
@@ -109,7 +116,7 @@ typedef long max_align_t;
     && defined __cplusplus
 # include <cstddef>
 #else
-# if ! (@HAVE_MAX_ALIGN_T@ || defined _GCC_MAX_ALIGN_T)
+# if ! (@HAVE_MAX_ALIGN_T@ || (defined _GCC_MAX_ALIGN_T && !defined __clang__))
 #  if !GNULIB_defined_max_align_t
 /* On the x86, the maximum storage alignment of double, long, etc. is 4,
    but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8,
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index 9edad426c..7e012621d 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -1202,6 +1202,47 @@ _GL_WARN_ON_USE (strtold, "strtold is unportable - "
 # endif
 #endif
 
+#if @GNULIB_STRTOL@
+/* Parse a signed integer whose textual representation starts at STRING.
+   The integer is expected to be in base BASE (2 <= BASE <= 36); if BASE == 0,
+   it may be decimal or octal (with prefix "0") or hexadecimal (with prefix
+   "0x").
+   If ENDPTR is not NULL, the address of the first byte after the integer is
+   stored in *ENDPTR.
+   Upon overflow, the return value is LONG_MAX or LONG_MIN, and errno is set
+   to ERANGE.  */
+# if @REPLACE_STRTOL@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define strtol rpl_strtol
+#  endif
+#  define GNULIB_defined_strtol_function 1
+_GL_FUNCDECL_RPL (strtol, long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base)
+                  _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (strtol, long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base));
+# else
+#  if !@HAVE_STRTOL@
+_GL_FUNCDECL_SYS (strtol, long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base)
+                  _GL_ARG_NONNULL ((1)));
+#  endif
+_GL_CXXALIAS_SYS (strtol, long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base));
+# endif
+_GL_CXXALIASWARN (strtol);
+#elif defined GNULIB_POSIXCHECK
+# undef strtol
+# if HAVE_RAW_DECL_STRTOL
+_GL_WARN_ON_USE (strtol, "strtol is unportable - "
+                 "use gnulib module strtol for portability");
+# endif
+#endif
+
 #if @GNULIB_STRTOLL@
 /* Parse a signed integer whose textual representation starts at STRING.
    The integer is expected to be in base BASE (2 <= BASE <= 36); if BASE == 0,
@@ -1211,15 +1252,29 @@ _GL_WARN_ON_USE (strtold, "strtold is unportable - "
    stored in *ENDPTR.
    Upon overflow, the return value is LLONG_MAX or LLONG_MIN, and errno is set
    to ERANGE.  */
-# if !@HAVE_STRTOLL@
+# if @REPLACE_STRTOLL@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define strtoll rpl_strtoll
+#  endif
+#  define GNULIB_defined_strtoll_function 1
+_GL_FUNCDECL_RPL (strtoll, long long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base)
+                  _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (strtoll, long long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base));
+# else
+#  if !@HAVE_STRTOLL@
 _GL_FUNCDECL_SYS (strtoll, long long,
                   (const char *restrict string, char **restrict endptr,
                    int base)
                   _GL_ARG_NONNULL ((1)));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (strtoll, long long,
                   (const char *restrict string, char **restrict endptr,
                    int base));
+# endif
 _GL_CXXALIASWARN (strtoll);
 #elif defined GNULIB_POSIXCHECK
 # undef strtoll
@@ -1229,6 +1284,46 @@ _GL_WARN_ON_USE (strtoll, "strtoll is unportable - "
 # endif
 #endif
 
+#if @GNULIB_STRTOUL@
+/* Parse an unsigned integer whose textual representation starts at STRING.
+   The integer is expected to be in base BASE (2 <= BASE <= 36); if BASE == 0,
+   it may be decimal or octal (with prefix "0") or hexadecimal (with prefix
+   "0x").
+   If ENDPTR is not NULL, the address of the first byte after the integer is
+   stored in *ENDPTR.
+   Upon overflow, the return value is ULONG_MAX, and errno is set to ERANGE.  */
+# if @REPLACE_STRTOUL@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define strtoul rpl_strtoul
+#  endif
+#  define GNULIB_defined_strtoul_function 1
+_GL_FUNCDECL_RPL (strtoul, unsigned long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base)
+                  _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (strtoul, unsigned long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base));
+# else
+#  if !@HAVE_STRTOUL@
+_GL_FUNCDECL_SYS (strtoul, unsigned long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base)
+                  _GL_ARG_NONNULL ((1)));
+#  endif
+_GL_CXXALIAS_SYS (strtoul, unsigned long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base));
+# endif
+_GL_CXXALIASWARN (strtoul);
+#elif defined GNULIB_POSIXCHECK
+# undef strtoul
+# if HAVE_RAW_DECL_STRTOUL
+_GL_WARN_ON_USE (strtoul, "strtoul is unportable - "
+                 "use gnulib module strtoul for portability");
+# endif
+#endif
+
 #if @GNULIB_STRTOULL@
 /* Parse an unsigned integer whose textual representation starts at STRING.
    The integer is expected to be in base BASE (2 <= BASE <= 36); if BASE == 0,
@@ -1238,15 +1333,29 @@ _GL_WARN_ON_USE (strtoll, "strtoll is unportable - "
    stored in *ENDPTR.
    Upon overflow, the return value is ULLONG_MAX, and errno is set to
    ERANGE.  */
-# if !@HAVE_STRTOULL@
+# if @REPLACE_STRTOULL@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   define strtoull rpl_strtoull
+#  endif
+#  define GNULIB_defined_strtoull_function 1
+_GL_FUNCDECL_RPL (strtoull, unsigned long long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base)
+                  _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (strtoull, unsigned long long,
+                  (const char *restrict string, char **restrict endptr,
+                   int base));
+# else
+#  if !@HAVE_STRTOULL@
 _GL_FUNCDECL_SYS (strtoull, unsigned long long,
                   (const char *restrict string, char **restrict endptr,
                    int base)
                   _GL_ARG_NONNULL ((1)));
-# endif
+#  endif
 _GL_CXXALIAS_SYS (strtoull, unsigned long long,
                   (const char *restrict string, char **restrict endptr,
                    int base));
+# endif
 _GL_CXXALIASWARN (strtoull);
 #elif defined GNULIB_POSIXCHECK
 # undef strtoull
diff --git a/lib/striconveh.c b/lib/striconveh.c
index d24d2d362..82f6467ba 100644
--- a/lib/striconveh.c
+++ b/lib/striconveh.c
@@ -499,11 +499,7 @@ mem_cd_iconveh_internal (const char *src, size_t srclen,
             else
               {
                 if (result != initial_result)
-                  {
-                    int saved_errno = errno;
-                    free (result);
-                    errno = saved_errno;
-                  }
+                  free (result);
                 return -1;
               }
           }
@@ -570,11 +566,7 @@ mem_cd_iconveh_internal (const char *src, size_t srclen,
           else
             {
               if (result != initial_result)
-                {
-                  int saved_errno = errno;
-                  free (result);
-                  errno = saved_errno;
-                }
+                free (result);
               return -1;
             }
         }
@@ -683,11 +675,7 @@ mem_cd_iconveh_internal (const char *src, size_t srclen,
             && !(errno == E2BIG || errno == EINVAL || errno == EILSEQ))
           {
             if (result != initial_result)
-              {
-                int saved_errno = errno;
-                free (result);
-                errno = saved_errno;
-              }
+              free (result);
             return -1;
           }
         if (res1 == (size_t)(-1)
@@ -907,22 +895,14 @@ mem_cd_iconveh_internal (const char *src, size_t srclen,
                           {
                             /* Failure converting the ASCII replacement.  */
                             if (result != initial_result)
-                              {
-                                int saved_errno = errno;
-                                free (result);
-                                errno = saved_errno;
-                              }
+                              free (result);
                             return -1;
                           }
                       }
                     else
                       {
                         if (result != initial_result)
-                          {
-                            int saved_errno = errno;
-                            free (result);
-                            errno = saved_errno;
-                          }
+                          free (result);
                         return -1;
                       }
                   }
@@ -1041,12 +1021,7 @@ str_cd_iconveh (const char *src,
 
   if (retval < 0)
     {
-      if (result != NULL)
-        {
-          int saved_errno = errno;
-          free (result);
-          errno = saved_errno;
-        }
+      free (result);
       return NULL;
     }
 
@@ -1118,12 +1093,8 @@ mem_iconveh (const char *src, size_t srclen,
         {
           if (iconveh_close (&cd) < 0)
             {
-              /* Return -1, but free the allocated memory, and while doing
-                 that, preserve the errno from iconveh_close.  */
-              int saved_errno = errno;
-              if (result != *resultp && result != NULL)
+              if (result != *resultp)
                 free (result);
-              errno = saved_errno;
               return -1;
             }
           *resultp = result;
@@ -1177,11 +1148,7 @@ str_iconveh (const char *src,
         {
           if (iconveh_close (&cd) < 0)
             {
-              /* Return NULL, but free the allocated memory, and while doing
-                 that, preserve the errno from iconveh_close.  */
-              int saved_errno = errno;
               free (result);
-              errno = saved_errno;
               return NULL;
             }
         }
diff --git a/lib/time.in.h b/lib/time.in.h
index fe1a1e81d..cbd2bbaf7 100644
--- a/lib/time.in.h
+++ b/lib/time.in.h
@@ -340,22 +340,60 @@ _GL_CXXALIASWARN (strftime);
 # endif
 
 # if defined _GNU_SOURCE && @GNULIB_TIME_RZ@ && ! @HAVE_TIMEZONE_T@
+/* Functions that use a first-class time zone data type, instead of
+   relying on an implicit global time zone.
+   Inspired by NetBSD.  */
+
+/* Represents a time zone.
+   (timezone_t) NULL stands for UTC.  */
 typedef struct tm_zone *timezone_t;
+
+/* tzalloc (name)
+   Returns a time zone object for the given time zone NAME.  This object
+   represents the time zone that other functions would use it the TZ
+   environment variable was set to NAME.
+   If NAME is NULL, the result represents the time zone that other functions
+   would use it the TZ environment variable was unset.
+   May return NULL if NAME is invalid (this is platform dependent) or
+   upon memory allocation failure.  */
 _GL_FUNCDECL_SYS (tzalloc, timezone_t, (char const *__name));
 _GL_CXXALIAS_SYS (tzalloc, timezone_t, (char const *__name));
+
+/* tzfree (tz)
+   Frees a time zone object.
+   The argument must have been returned by tzalloc().  */
 _GL_FUNCDECL_SYS (tzfree, void, (timezone_t __tz));
 _GL_CXXALIAS_SYS (tzfree, void, (timezone_t __tz));
+
+/* localtime_rz (tz, &t, &result)
+   Converts an absolute time T to a broken-down time RESULT, assuming the
+   time zone TZ.
+   This function is like 'localtime_r', but relies on the argument TZ instead
+   of an implicit global time zone.  */
 _GL_FUNCDECL_SYS (localtime_rz, struct tm *,
                   (timezone_t __tz, time_t const *restrict __timer,
                    struct tm *restrict __result) _GL_ARG_NONNULL ((2, 3)));
 _GL_CXXALIAS_SYS (localtime_rz, struct tm *,
                   (timezone_t __tz, time_t const *restrict __timer,
                    struct tm *restrict __result));
+
+/* mktime_z (tz, &tm)
+   Normalizes the broken-down time TM and converts it to an absolute time,
+   assuming the time zone TZ.  Returns the absolute time.
+   This function is like 'mktime', but relies on the argument TZ instead
+   of an implicit global time zone.  */
 _GL_FUNCDECL_SYS (mktime_z, time_t,
-                  (timezone_t __tz, struct tm *restrict __result)
+                  (timezone_t __tz, struct tm *restrict __tm)
                   _GL_ARG_NONNULL ((2)));
 _GL_CXXALIAS_SYS (mktime_z, time_t,
-                  (timezone_t __tz, struct tm *restrict __result));
+                  (timezone_t __tz, struct tm *restrict __tm));
+
+/* Time zone abbreviation strings (returned by 'localtime_rz' or 'mktime_z'
+   in the 'tm_zone' member of 'struct tm') are valid as long as
+     - the 'struct tm' argument is not destroyed or overwritten,
+   and
+     - the 'timezone_t' argument is not freed through tzfree().  */
+
 # endif
 
 /* Convert TM to a time_t value, assuming UTC.  */
diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c
index a6249ff3c..8d5100695 100644
--- a/lib/vasnprintf.c
+++ b/lib/vasnprintf.c
@@ -1859,6 +1859,7 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
     /* errno is already set.  */
     return NULL;
 
+  /* Frees the memory allocated by this function.  Preserves errno.  */
 #define CLEANUP() \
   if (d.dir != d.direct_alloc_dir)                                      \
     free (d.dir);                                                       \
@@ -2183,13 +2184,11 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
 #  endif
                         if (converted == NULL)
                           {
-                            int saved_errno = errno;
                             if (!(result == resultbuf || result == NULL))
                               free (result);
                             if (buf_malloced != NULL)
                               free (buf_malloced);
                             CLEANUP ();
-                            errno = saved_errno;
                             return NULL;
                           }
                         if (converted != result + length)
@@ -2309,13 +2308,11 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
 #  endif
                         if (converted == NULL)
                           {
-                            int saved_errno = errno;
                             if (!(result == resultbuf || result == NULL))
                               free (result);
                             if (buf_malloced != NULL)
                               free (buf_malloced);
                             CLEANUP ();
-                            errno = saved_errno;
                             return NULL;
                           }
                         if (converted != result + length)
@@ -2435,13 +2432,11 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
 #  endif
                         if (converted == NULL)
                           {
-                            int saved_errno = errno;
                             if (!(result == resultbuf || result == NULL))
                               free (result);
                             if (buf_malloced != NULL)
                               free (buf_malloced);
                             CLEANUP ();
-                            errno = saved_errno;
                             return NULL;
                           }
                         if (converted != result + length)
@@ -2852,14 +2847,12 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                                               NULL, &tmpdst_len);
                   if (tmpdst == NULL)
                     {
-                      int saved_errno = errno;
                       free (tmpsrc);
                       if (!(result == resultbuf || result == NULL))
                         free (result);
                       if (buf_malloced != NULL)
                         free (buf_malloced);
                       CLEANUP ();
-                      errno = saved_errno;
                       return NULL;
                     }
                   free (tmpsrc);
@@ -3079,13 +3072,11 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                                               NULL, &tmpdst_len);
                   if (tmpdst == NULL)
                     {
-                      int saved_errno = errno;
                       if (!(result == resultbuf || result == NULL))
                         free (result);
                       if (buf_malloced != NULL)
                         free (buf_malloced);
                       CLEANUP ();
-                      errno = saved_errno;
                       return NULL;
                     }
 # endif
@@ -5449,15 +5440,14 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                     /* Attempt to handle failure.  */
                     if (count < 0)
                       {
-                        /* SNPRINTF or sprintf failed.  Save and use the errno
-                           that it has set, if any.  */
-                        int saved_errno = errno;
-                        if (saved_errno == 0)
+                        /* SNPRINTF or sprintf failed.  Use the errno that it
+                           has set, if any.  */
+                        if (errno == 0)
                           {
                             if (dp->conversion == 'c' || dp->conversion == 's')
-                              saved_errno = EILSEQ;
+                              errno = EILSEQ;
                             else
-                              saved_errno = EINVAL;
+                              errno = EINVAL;
                           }
 
                         if (!(result == resultbuf || result == NULL))
@@ -5466,7 +5456,6 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                           free (buf_malloced);
                         CLEANUP ();
 
-                        errno = saved_errno;
                         return NULL;
                       }
 
@@ -5602,13 +5591,11 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                                                     NULL, &tmpdst_len);
                         if (tmpdst == NULL)
                           {
-                            int saved_errno = errno;
                             if (!(result == resultbuf || result == NULL))
                               free (result);
                             if (buf_malloced != NULL)
                               free (buf_malloced);
                             CLEANUP ();
-                            errno = saved_errno;
                             return NULL;
                           }
                         ENSURE_ALLOCATION (xsum (length, tmpdst_len));
diff --git a/lib/xalloc-oversized.h b/lib/xalloc-oversized.h
index 36a05d5ce..d25596932 100644
--- a/lib/xalloc-oversized.h
+++ b/lib/xalloc-oversized.h
@@ -21,34 +21,34 @@
 #include <stddef.h>
 #include <stdint.h>
 
-/* True if N * S would overflow in a size_t calculation,
-   or would generate a value larger than PTRDIFF_MAX.
+/* True if N * S does not fit into both ptrdiff_t and size_t.
+   S must be positive and N must be nonnegative.
    This expands to a constant expression if N and S are both constants.
-   By gnulib convention, SIZE_MAX represents overflow in size
+   By gnulib convention, SIZE_MAX represents overflow in size_t
    calculations, so the conservative size_t-based dividend to use here
    is SIZE_MAX - 1.  */
 #define __xalloc_oversized(n, s) \
   ((size_t) (PTRDIFF_MAX < SIZE_MAX ? PTRDIFF_MAX : SIZE_MAX - 1) / (s) < (n))
 
 #if PTRDIFF_MAX < SIZE_MAX
-typedef ptrdiff_t __xalloc_count_type;
+typedef ptrdiff_t xalloc_count_t;
 #else
-typedef size_t __xalloc_count_type;
+typedef size_t xalloc_count_t;
 #endif
 
-/* Return 1 if an array of N objects, each of size S, cannot exist
-   reliably due to size or ptrdiff_t arithmetic overflow.  S must be
-   positive and N must be nonnegative.  This is a macro, not a
-   function, so that it works correctly even when SIZE_MAX < N.  */
-
+/* Return 1 if an array of N objects, each of size S, cannot exist reliably
+   because its total size in bytes exceeds MIN (PTRDIFF_MAX, SIZE_MAX).
+   N must be nonnegative, S must be positive, and either N or S should be
+   of type ptrdiff_t or size_t or wider.  This is a macro, not a function,
+   so that it works even if an argument exceeds MAX (PTRDIFF_MAX, SIZE_MAX).  */
 #if 7 <= __GNUC__ && !defined __clang__
 # define xalloc_oversized(n, s) \
-   __builtin_mul_overflow_p (n, s, (__xalloc_count_type) 1)
+   __builtin_mul_overflow_p (n, s, (xalloc_count_t) 1)
 #elif 5 <= __GNUC__ && !defined __ICC && !__STRICT_ANSI__
 # define xalloc_oversized(n, s) \
    (__builtin_constant_p (n) && __builtin_constant_p (s) \
     ? __xalloc_oversized (n, s) \
-    : ({ __xalloc_count_type __xalloc_count; \
+    : ({ xalloc_count_t __xalloc_count; \
          __builtin_mul_overflow (n, s, &__xalloc_count); }))
 
 /* Other compilers use integer division; this may be slower but is
diff --git a/m4/canonicalize.m4 b/m4/canonicalize.m4
index 6821c70e6..0dfb2da9a 100644
--- a/m4/canonicalize.m4
+++ b/m4/canonicalize.m4
@@ -1,4 +1,4 @@
-# canonicalize.m4 serial 36
+# canonicalize.m4 serial 37
 
 dnl Copyright (C) 2003-2007, 2009-2021 Free Software Foundation, Inc.
 
@@ -78,15 +78,20 @@ AC_DEFUN([gl_CANONICALIZE_LGPL_SEPARATE],
 # so is the latter.
 AC_DEFUN([gl_FUNC_REALPATH_WORKS],
 [
-  AC_CHECK_FUNCS_ONCE([realpath])
+  AC_CHECK_FUNCS_ONCE([realpath lstat])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_CACHE_CHECK([whether realpath works], [gl_cv_func_realpath_works], [
     rm -rf conftest.a conftest.d
     touch conftest.a
+    # Assume that if we have lstat, we can also check symlinks.
+    if test $ac_cv_func_lstat = yes; then
+      ln -s conftest.a conftest.l
+    fi
     mkdir conftest.d
     AC_RUN_IFELSE([
       AC_LANG_PROGRAM([[
         ]GL_NOCRASH[
+        #include <errno.h>
         #include <stdlib.h>
         #include <string.h>
       ]], [[
@@ -98,17 +103,27 @@ AC_DEFUN([gl_FUNC_REALPATH_WORKS],
             result |= 1;
           free (name);
         }
+        /* This test fails on older versions of Cygwin.  */
         {
           char *name = realpath ("conftest.b/../conftest.a", NULL);
           if (name != NULL)
             result |= 2;
           free (name);
         }
+        /* This test fails on Cygwin 2.9.  */
+        #if HAVE_LSTAT
+        {
+          char *name = realpath ("conftest.l/../conftest.a", NULL);
+          if (name != NULL || errno != ENOTDIR)
+            result |= 4;
+          free (name);
+        }
+        #endif
         /* This test fails on Mac OS X 10.13, OpenBSD 6.0.  */
         {
           char *name = realpath ("conftest.a/", NULL);
           if (name != NULL)
-            result |= 4;
+            result |= 8;
           free (name);
         }
         /* This test fails on AIX 7, Solaris 10.  */
@@ -116,7 +131,7 @@ AC_DEFUN([gl_FUNC_REALPATH_WORKS],
           char *name1 = realpath (".", NULL);
           char *name2 = realpath ("conftest.d//./..", NULL);
           if (! name1 || ! name2 || strcmp (name1, name2))
-            result |= 8;
+            result |= 16;
           free (name1);
           free (name2);
         }
@@ -127,7 +142,7 @@ AC_DEFUN([gl_FUNC_REALPATH_WORKS],
         {
           char *name = realpath ("//", NULL);
           if (! name || strcmp (name, "/"))
-            result |= 16;
+            result |= 32;
           free (name);
         }
         #endif
@@ -136,7 +151,7 @@ AC_DEFUN([gl_FUNC_REALPATH_WORKS],
      ],
      [gl_cv_func_realpath_works=yes],
      [case $? in
-        16) gl_cv_func_realpath_works=nearly ;;
+        32) gl_cv_func_realpath_works=nearly ;;
         *)  gl_cv_func_realpath_works=no ;;
       esac
      ],
@@ -145,13 +160,15 @@ AC_DEFUN([gl_FUNC_REALPATH_WORKS],
         *-gnu* | gnu*) gl_cv_func_realpath_works="guessing yes" ;;
                        # Guess 'nearly' on musl systems.
         *-musl*)       gl_cv_func_realpath_works="guessing nearly" ;;
+                       # Guess no on Cygwin.
+        cygwin*)       gl_cv_func_realpath_works="guessing no" ;;
                        # Guess no on native Windows.
         mingw*)        gl_cv_func_realpath_works="guessing no" ;;
                        # If we don't know, obey --enable-cross-guesses.
         *)             gl_cv_func_realpath_works="$gl_cross_guess_normal" ;;
       esac
      ])
-    rm -rf conftest.a conftest.d
+    rm -rf conftest.a conftest.l conftest.d
   ])
   case "$gl_cv_func_realpath_works" in
     *yes)
diff --git a/m4/free.m4 b/m4/free.m4
index d671376b0..a7923b905 100644
--- a/m4/free.m4
+++ b/m4/free.m4
@@ -1,4 +1,4 @@
-# free.m4 serial 5
+# free.m4 serial 6
 # Copyright (C) 2003-2005, 2009-2021 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
@@ -40,7 +40,10 @@ AC_DEFUN([gl_FUNC_FREE],
     ])
 
   case $gl_cv_func_free_preserves_errno in
-   *yes) ;;
+   *yes)
+    AC_DEFINE([HAVE_FREE_POSIX], [1],
+      [Define if the 'free' function is guaranteed to preserve errno.])
+    ;;
    *) REPLACE_FREE=1 ;;
   esac
 ])
diff --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4
index 3d87fd840..f2eff10de 100644
--- a/m4/gnulib-common.m4
+++ b/m4/gnulib-common.m4
@@ -67,7 +67,9 @@ AC_DEFUN([gl_COMMON_BODY], [
 #endif])
   AH_VERBATIM([attribute],
 [/* Attributes.  */
-#ifdef __has_attribute
+#if (defined __has_attribute \
+     && (!defined __clang_minor__ \
+         || 3 < __clang_major__ + (5 <= __clang_minor__)))
 # define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
 #else
 # define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index 723c91342..1290d7589 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -191,6 +191,7 @@ AC_DEFUN([gl_EARLY],
   # Code from module rawmemchr:
   # Code from module read:
   # Code from module readlink:
+  # Code from module realloc-posix:
   # Code from module recv:
   # Code from module recvfrom:
   # Code from module regex:
@@ -365,6 +366,12 @@ AC_DEFUN([gl_INIT],
     AC_LIBOBJ([floor])
   fi
   gl_MATH_MODULE_INDICATOR([floor])
+  gl_FUNC_FREE
+  if test $REPLACE_FREE = 1; then
+    AC_LIBOBJ([free])
+    gl_PREREQ_FREE
+  fi
+  gl_STDLIB_MODULE_INDICATOR([free-posix])
   AC_REQUIRE([gl_FUNC_FREXP])
   if test $gl_func_frexp != yes; then
     AC_LIBOBJ([frexp])
@@ -540,6 +547,7 @@ AC_DEFUN([gl_INIT],
     AC_LIBOBJ([malloc])
   fi
   gl_STDLIB_MODULE_INDICATOR([malloc-posix])
+  gl_MODULE_INDICATOR([malloc-posix])
   gl_MALLOCA
   gl_MATH_H
   gl_MINMAX
@@ -758,7 +766,6 @@ AC_DEFUN([gl_INIT],
   gl_gnulib_enabled_925677f0343de64b89a9f0c790b4104c=false
   gl_gnulib_enabled_fcntl=false
   gl_gnulib_enabled_43fe87a341d9b4b93c47c3ad819a5239=false
-  gl_gnulib_enabled_ef07dc4b3077c11ea9cef586db4e5955=false
   gl_gnulib_enabled_getdtablesize=false
   gl_gnulib_enabled_getrandom=false
   gl_gnulib_enabled_be453cec5eecf5731a274f2de7f2db36=false
@@ -781,6 +788,7 @@ AC_DEFUN([gl_INIT],
   gl_gnulib_enabled_pathmax=false
   gl_gnulib_enabled_raise=false
   gl_gnulib_enabled_rawmemchr=false
+  gl_gnulib_enabled_61bcaca76b3e6f9ae55d57a1c3193bc4=false
   gl_gnulib_enabled_round=false
   gl_gnulib_enabled_9bc5f216d57e231e4834049d67d0db62=false
   gl_gnulib_enabled_scratch_buffer=false
@@ -905,18 +913,6 @@ AC_SUBST([LTALLOCA])
       gl_gnulib_enabled_43fe87a341d9b4b93c47c3ad819a5239=true
     fi
   }
-  func_gl_gnulib_m4code_ef07dc4b3077c11ea9cef586db4e5955 ()
-  {
-    if ! $gl_gnulib_enabled_ef07dc4b3077c11ea9cef586db4e5955; then
-      gl_FUNC_FREE
-      if test $REPLACE_FREE = 1; then
-        AC_LIBOBJ([free])
-        gl_PREREQ_FREE
-      fi
-      gl_STDLIB_MODULE_INDICATOR([free-posix])
-      gl_gnulib_enabled_ef07dc4b3077c11ea9cef586db4e5955=true
-    fi
-  }
   func_gl_gnulib_m4code_getdtablesize ()
   {
     if ! $gl_gnulib_enabled_getdtablesize; then
@@ -1177,6 +1173,18 @@ AC_SUBST([LTALLOCA])
       gl_gnulib_enabled_rawmemchr=true
     fi
   }
+  func_gl_gnulib_m4code_61bcaca76b3e6f9ae55d57a1c3193bc4 ()
+  {
+    if ! $gl_gnulib_enabled_61bcaca76b3e6f9ae55d57a1c3193bc4; then
+      gl_FUNC_REALLOC_POSIX
+      if test $REPLACE_REALLOC = 1; then
+        AC_LIBOBJ([realloc])
+      fi
+      gl_STDLIB_MODULE_INDICATOR([realloc-posix])
+      gl_MODULE_INDICATOR([realloc-posix])
+      gl_gnulib_enabled_61bcaca76b3e6f9ae55d57a1c3193bc4=true
+    fi
+  }
   func_gl_gnulib_m4code_round ()
   {
     if ! $gl_gnulib_enabled_round; then
@@ -1199,6 +1207,7 @@ AC_SUBST([LTALLOCA])
     if ! $gl_gnulib_enabled_scratch_buffer; then
       gl_gnulib_enabled_scratch_buffer=true
       func_gl_gnulib_m4code_21ee726a3540c09237a8e70c0baf7467
+      func_gl_gnulib_m4code_61bcaca76b3e6f9ae55d57a1c3193bc4
     fi
   }
   func_gl_gnulib_m4code_servent ()
@@ -1422,9 +1431,6 @@ AC_SUBST([LTALLOCA])
     func_gl_gnulib_m4code_925677f0343de64b89a9f0c790b4104c
   fi
   if test $HAVE_CANONICALIZE_FILE_NAME = 0 || test $REPLACE_CANONICALIZE_FILE_NAME = 1; then
-    func_gl_gnulib_m4code_ef07dc4b3077c11ea9cef586db4e5955
-  fi
-  if test $HAVE_CANONICALIZE_FILE_NAME = 0 || test $REPLACE_CANONICALIZE_FILE_NAME = 1; then
     func_gl_gnulib_m4code_idx
   fi
   if test $HAVE_CANONICALIZE_FILE_NAME = 0 || test $REPLACE_CANONICALIZE_FILE_NAME = 1; then
@@ -1610,7 +1616,6 @@ AC_SUBST([LTALLOCA])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_925677f0343de64b89a9f0c790b4104c], [$gl_gnulib_enabled_925677f0343de64b89a9f0c790b4104c])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_fcntl], [$gl_gnulib_enabled_fcntl])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_43fe87a341d9b4b93c47c3ad819a5239], [$gl_gnulib_enabled_43fe87a341d9b4b93c47c3ad819a5239])
-  AM_CONDITIONAL([gl_GNULIB_ENABLED_ef07dc4b3077c11ea9cef586db4e5955], [$gl_gnulib_enabled_ef07dc4b3077c11ea9cef586db4e5955])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_getdtablesize], [$gl_gnulib_enabled_getdtablesize])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_getrandom], [$gl_gnulib_enabled_getrandom])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_be453cec5eecf5731a274f2de7f2db36], [$gl_gnulib_enabled_be453cec5eecf5731a274f2de7f2db36])
@@ -1633,6 +1638,7 @@ AC_SUBST([LTALLOCA])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_pathmax], [$gl_gnulib_enabled_pathmax])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_raise], [$gl_gnulib_enabled_raise])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_rawmemchr], [$gl_gnulib_enabled_rawmemchr])
+  AM_CONDITIONAL([gl_GNULIB_ENABLED_61bcaca76b3e6f9ae55d57a1c3193bc4], [$gl_gnulib_enabled_61bcaca76b3e6f9ae55d57a1c3193bc4])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_round], [$gl_gnulib_enabled_round])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_9bc5f216d57e231e4834049d67d0db62], [$gl_gnulib_enabled_9bc5f216d57e231e4834049d67d0db62])
   AM_CONDITIONAL([gl_GNULIB_ENABLED_scratch_buffer], [$gl_gnulib_enabled_scratch_buffer])
@@ -1976,6 +1982,7 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/rawmemchr.valgrind
   lib/read.c
   lib/readlink.c
+  lib/realloc.c
   lib/recv.c
   lib/recvfrom.c
   lib/regcomp.c
@@ -2194,6 +2201,7 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/rawmemchr.m4
   m4/read.m4
   m4/readlink.m4
+  m4/realloc.m4
   m4/regex.m4
   m4/rename.m4
   m4/rmdir.m4
diff --git a/m4/host-cpu-c-abi.m4 b/m4/host-cpu-c-abi.m4
index 7dc830eff..64e28b1d3 100644
--- a/m4/host-cpu-c-abi.m4
+++ b/m4/host-cpu-c-abi.m4
@@ -1,4 +1,4 @@
-# host-cpu-c-abi.m4 serial 13
+# host-cpu-c-abi.m4 serial 14
 dnl Copyright (C) 2002-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -211,7 +211,7 @@ changequote([,])dnl
          # be generating 64-bit code.
          AC_COMPILE_IFELSE(
            [AC_LANG_SOURCE(
-              [[#if defined __powerpc64__ || defined _ARCH_PPC64
+              [[#if defined __powerpc64__ || defined __LP64__
                  int ok;
                 #else
                  error fail
@@ -605,7 +605,7 @@ changequote([,])dnl
            # be generating 64-bit code.
            AC_COMPILE_IFELSE(
              [AC_LANG_SOURCE(
-                [[#if defined __powerpc64__ || defined _ARCH_PPC64
+                [[#if defined __powerpc64__ || defined __LP64__
                    int ok;
                   #else
                    error fail
diff --git a/m4/lib-ld.m4 b/m4/lib-ld.m4
index aa07cb4bc..076358d5d 100644
--- a/m4/lib-ld.m4
+++ b/m4/lib-ld.m4
@@ -1,4 +1,4 @@
-# lib-ld.m4 serial 9
+# lib-ld.m4 serial 10
 dnl Copyright (C) 1996-2003, 2009-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -122,7 +122,7 @@ else
       *-*-aix*)
         AC_COMPILE_IFELSE(
           [AC_LANG_SOURCE(
-             [[#if defined __powerpc64__ || defined _ARCH_PPC64
+             [[#if defined __powerpc64__ || defined __LP64__
                 int ok;
                #else
                 error fail
diff --git a/m4/malloc.m4 b/m4/malloc.m4
index 514d19a90..32ab42ec0 100644
--- a/m4/malloc.m4
+++ b/m4/malloc.m4
@@ -1,4 +1,4 @@
-# malloc.m4 serial 21
+# malloc.m4 serial 22
 dnl Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -24,7 +24,7 @@ AC_DEFUN([_AC_FUNC_MALLOC_IF],
        [ac_cv_func_malloc_0_nonnull=no],
        [case "$host_os" in
           # Guess yes on platforms where we know the result.
-          *-gnu* | gnu* | *-musl* | freebsd* | netbsd* | openbsd* \
+          *-gnu* | gnu* | *-musl* | freebsd* | midnightbsd* | netbsd* | openbsd* \
           | hpux* | solaris* | cygwin* | mingw*)
             ac_cv_func_malloc_0_nonnull="guessing yes" ;;
           # If we don't know, obey --enable-cross-guesses.
diff --git a/m4/printf.m4 b/m4/printf.m4
index c8e74e22c..d8b352104 100644
--- a/m4/printf.m4
+++ b/m4/printf.m4
@@ -1,4 +1,4 @@
-# printf.m4 serial 71
+# printf.m4 serial 72
 dnl Copyright (C) 2003, 2007-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -67,6 +67,7 @@ changequote(,)dnl
                                  # Guess yes on FreeBSD >= 5.
            freebsd[1-4].*)       gl_cv_func_printf_sizes_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_printf_sizes_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_printf_sizes_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_printf_sizes_c99="guessing no";;
            darwin*)              gl_cv_func_printf_sizes_c99="guessing yes";;
@@ -247,6 +248,7 @@ changequote(,)dnl
                                  # Guess yes on FreeBSD >= 6.
            freebsd[1-5].*)       gl_cv_func_printf_infinite="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_printf_infinite="guessing yes";;
+           midnightbsd*)         gl_cv_func_printf_infinite="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_printf_infinite="guessing no";;
            darwin*)              gl_cv_func_printf_infinite="guessing yes";;
@@ -469,6 +471,7 @@ changequote(,)dnl
                                          # Guess yes on FreeBSD >= 6.
                    freebsd[1-5].*)       gl_cv_func_printf_infinite_long_double="guessing no";;
                    freebsd* | kfreebsd*) gl_cv_func_printf_infinite_long_double="guessing yes";;
+                   midnightbsd*)         gl_cv_func_printf_infinite_long_double="guessing yes";;
                                          # Guess yes on HP-UX >= 11.
                    hpux[7-9]* | hpux10*) gl_cv_func_printf_infinite_long_double="guessing no";;
                    hpux*)                gl_cv_func_printf_infinite_long_double="guessing yes";;
@@ -644,6 +647,7 @@ changequote(,)dnl
                                  # Guess yes on FreeBSD >= 6.
            freebsd[1-5].*)       gl_cv_func_printf_directive_f="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_printf_directive_f="guessing yes";;
+           midnightbsd*)         gl_cv_func_printf_directive_f="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_printf_directive_f="guessing no";;
            darwin*)              gl_cv_func_printf_directive_f="guessing yes";;
@@ -1239,6 +1243,7 @@ changequote(,)dnl
                                  # Guess yes on FreeBSD >= 5.
            freebsd[1-4].*)       gl_cv_func_snprintf_truncation_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_snprintf_truncation_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_snprintf_truncation_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_snprintf_truncation_c99="guessing no";;
            darwin*)              gl_cv_func_snprintf_truncation_c99="guessing yes";;
@@ -1343,6 +1348,7 @@ changequote(,)dnl
                                  # Guess yes on FreeBSD >= 5.
            freebsd[1-4].*)       gl_cv_func_snprintf_retval_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_snprintf_retval_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_snprintf_retval_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_snprintf_retval_c99="guessing no";;
            darwin*)              gl_cv_func_snprintf_retval_c99="guessing yes";;
@@ -1445,6 +1451,7 @@ changequote(,)dnl
                                  # Guess yes on FreeBSD >= 5.
            freebsd[1-4].*)       gl_cv_func_snprintf_directive_n="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_snprintf_directive_n="guessing yes";;
+           midnightbsd*)         gl_cv_func_snprintf_directive_n="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_snprintf_directive_n="guessing no";;
            darwin*)              gl_cv_func_snprintf_directive_n="guessing yes";;
@@ -1601,6 +1608,7 @@ changequote(,)dnl
                                  # Guess yes on FreeBSD >= 5.
            freebsd[1-4].*)       gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
            freebsd* | kfreebsd*) gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
+           midnightbsd*)         gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
                                  # Guess yes on Mac OS X >= 10.3.
            darwin[1-6].*)        gl_cv_func_vsnprintf_zerosize_c99="guessing no";;
            darwin*)              gl_cv_func_vsnprintf_zerosize_c99="guessing yes";;
diff --git a/m4/realloc.m4 b/m4/realloc.m4
new file mode 100644
index 000000000..a80a02a6b
--- /dev/null
+++ b/m4/realloc.m4
@@ -0,0 +1,76 @@
+# realloc.m4 serial 20
+dnl Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+# This is adapted with modifications from upstream Autoconf here:
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=04be2b7a29d65d9a08e64e8e56e594c91749598c
+AC_DEFUN([_AC_FUNC_REALLOC_IF],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+  AC_CACHE_CHECK([for GNU libc compatible realloc],
+    [ac_cv_func_realloc_0_nonnull],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <stdlib.h>
+          ]],
+          [[char *p = realloc (0, 0);
+            int result = !p;
+            free (p);
+            return result;]])
+       ],
+       [ac_cv_func_realloc_0_nonnull=yes],
+       [ac_cv_func_realloc_0_nonnull=no],
+       [case "$host_os" in
+          # Guess yes on platforms where we know the result.
+          *-gnu* | gnu* | *-musl* | freebsd* | midnightbsd* | netbsd* | openbsd* \
+          | hpux* | solaris* | cygwin* | mingw*)
+            ac_cv_func_realloc_0_nonnull="guessing yes" ;;
+          # If we don't know, obey --enable-cross-guesses.
+          *) ac_cv_func_realloc_0_nonnull="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
+  case "$ac_cv_func_realloc_0_nonnull" in
+    *yes)
+      $1
+      ;;
+    *)
+      $2
+      ;;
+  esac
+])# AC_FUNC_REALLOC
+
+# gl_FUNC_REALLOC_GNU
+# -------------------
+# Test whether 'realloc (0, 0)' is handled like in GNU libc, and replace
+# realloc if it is not.
+AC_DEFUN([gl_FUNC_REALLOC_GNU],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  dnl _AC_FUNC_REALLOC_IF is defined in Autoconf.
+  _AC_FUNC_REALLOC_IF(
+    [AC_DEFINE([HAVE_REALLOC_GNU], [1],
+               [Define to 1 if your system has a GNU libc compatible 'realloc'
+                function, and to 0 otherwise.])],
+    [AC_DEFINE([HAVE_REALLOC_GNU], [0])
+     REPLACE_REALLOC=1
+    ])
+])# gl_FUNC_REALLOC_GNU
+
+# gl_FUNC_REALLOC_POSIX
+# ---------------------
+# Test whether 'realloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails), and replace realloc if it is not.
+AC_DEFUN([gl_FUNC_REALLOC_POSIX],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix = yes; then
+    AC_DEFINE([HAVE_REALLOC_POSIX], [1],
+      [Define if the 'realloc' function is POSIX compliant.])
+  else
+    REPLACE_REALLOC=1
+  fi
+])
diff --git a/m4/setlocale_null.m4 b/m4/setlocale_null.m4
index c486ca840..2c958ed77 100644
--- a/m4/setlocale_null.m4
+++ b/m4/setlocale_null.m4
@@ -1,4 +1,4 @@
-# setlocale_null.m4 serial 4
+# setlocale_null.m4 serial 5
 dnl Copyright (C) 2019-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,7 +14,7 @@ AC_DEFUN([gl_FUNC_SETLOCALE_NULL],
     [gl_cv_func_setlocale_null_all_mtsafe],
     [case "$host_os" in
        # Guess no on musl libc, macOS, FreeBSD, NetBSD, OpenBSD, AIX, Haiku, Cygwin.
-       *-musl* | darwin* | freebsd* | netbsd* | openbsd* | aix* | haiku* | cygwin*)
+       *-musl* | darwin* | freebsd* | midnightbsd* | netbsd* | openbsd* | aix* | haiku* | cygwin*)
          gl_cv_func_setlocale_null_all_mtsafe=no ;;
        # Guess yes on glibc, HP-UX, IRIX, Solaris, native Windows.
        *-gnu* | gnu* | hpux* | irix* | solaris* | mingw*)
@@ -48,7 +48,7 @@ AC_DEFUN([gl_FUNC_SETLOCALE_NULL],
        openbsd* | aix*)
          gl_cv_func_setlocale_null_one_mtsafe=no ;;
        # Guess yes on glibc, musl libc, macOS, FreeBSD, NetBSD, HP-UX, IRIX, Solaris, Haiku, Cygwin, native Windows.
-       *-gnu* | gnu* | *-musl* | darwin* | freebsd* | netbsd* | hpux* | irix* | solaris* | haiku* | cygwin* | mingw*)
+       *-gnu* | gnu* | *-musl* | darwin* | freebsd* | midnightbsd* | netbsd* | hpux* | irix* | solaris* | haiku* | cygwin* | mingw*)
          gl_cv_func_setlocale_null_one_mtsafe=yes ;;
        # If we don't know, obey --enable-cross-guesses.
        *)
diff --git a/m4/stdalign.m4 b/m4/stdalign.m4
index 8dcb634d5..e22d7f78c 100644
--- a/m4/stdalign.m4
+++ b/m4/stdalign.m4
@@ -13,7 +13,8 @@ AC_DEFUN([gl_STDALIGN_H],
     [gl_cv_header_working_stdalign_h],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM(
-          [[#include <stdalign.h>
+          [[#include <stdint.h>
+            #include <stdalign.h>
             #include <stddef.h>
 
             /* Test that alignof yields a result consistent with offsetof.
@@ -32,6 +33,7 @@ AC_DEFUN([gl_STDALIGN_H],
             /* Test _Alignas only on platforms where gnulib can help.  */
             #if \
                 ((defined __cplusplus && 201103 <= __cplusplus) \
+                 || (__TINYC__ && defined __attribute__) \
                  || (defined __APPLE__ && defined __MACH__ \
                      ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
                      : __GNUC__) \
diff --git a/m4/stdlib_h.m4 b/m4/stdlib_h.m4
index 5a02972e0..5fdb0a706 100644
--- a/m4/stdlib_h.m4
+++ b/m4/stdlib_h.m4
@@ -1,4 +1,4 @@
-# stdlib_h.m4 serial 55
+# stdlib_h.m4 serial 59
 dnl Copyright (C) 2007-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -28,7 +28,7 @@ AC_DEFUN([gl_STDLIB_H],
     posix_memalign posix_openpt ptsname ptsname_r qsort_r
     random random_r reallocarray realpath rpmatch secure_getenv setenv
     setstate setstate_r srandom srandom_r
-    strtod strtold strtoll strtoull unlockpt unsetenv])
+    strtod strtol strtold strtoll strtoul strtoull unlockpt unsetenv])
 
   AC_REQUIRE([AC_C_RESTRICT])
 
@@ -88,8 +88,10 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   GNULIB_SECURE_GETENV=0; AC_SUBST([GNULIB_SECURE_GETENV])
   GNULIB_SETENV=0;        AC_SUBST([GNULIB_SETENV])
   GNULIB_STRTOD=0;        AC_SUBST([GNULIB_STRTOD])
+  GNULIB_STRTOL=0;        AC_SUBST([GNULIB_STRTOL])
   GNULIB_STRTOLD=0;       AC_SUBST([GNULIB_STRTOLD])
   GNULIB_STRTOLL=0;       AC_SUBST([GNULIB_STRTOLL])
+  GNULIB_STRTOUL=0;       AC_SUBST([GNULIB_STRTOUL])
   GNULIB_STRTOULL=0;      AC_SUBST([GNULIB_STRTOULL])
   GNULIB_SYSTEM_POSIX=0;  AC_SUBST([GNULIB_SYSTEM_POSIX])
   GNULIB_UNLOCKPT=0;      AC_SUBST([GNULIB_UNLOCKPT])
@@ -137,8 +139,10 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   HAVE_SETSTATE=1;           AC_SUBST([HAVE_SETSTATE])
   HAVE_DECL_SETSTATE=1;      AC_SUBST([HAVE_DECL_SETSTATE])
   HAVE_STRTOD=1;             AC_SUBST([HAVE_STRTOD])
+  HAVE_STRTOL=1;             AC_SUBST([HAVE_STRTOL])
   HAVE_STRTOLD=1;            AC_SUBST([HAVE_STRTOLD])
   HAVE_STRTOLL=1;            AC_SUBST([HAVE_STRTOLL])
+  HAVE_STRTOUL=1;            AC_SUBST([HAVE_STRTOUL])
   HAVE_STRTOULL=1;           AC_SUBST([HAVE_STRTOULL])
   HAVE_STRUCT_RANDOM_DATA=1; AC_SUBST([HAVE_STRUCT_RANDOM_DATA])
   HAVE_SYS_LOADAVG_H=0;      AC_SUBST([HAVE_SYS_LOADAVG_H])
@@ -164,7 +168,11 @@ AC_DEFUN([gl_STDLIB_H_DEFAULTS],
   REPLACE_SETENV=0;          AC_SUBST([REPLACE_SETENV])
   REPLACE_SETSTATE=0;        AC_SUBST([REPLACE_SETSTATE])
   REPLACE_STRTOD=0;          AC_SUBST([REPLACE_STRTOD])
+  REPLACE_STRTOL=0;          AC_SUBST([REPLACE_STRTOL])
   REPLACE_STRTOLD=0;         AC_SUBST([REPLACE_STRTOLD])
+  REPLACE_STRTOLL=0;         AC_SUBST([REPLACE_STRTOLL])
+  REPLACE_STRTOUL=0;         AC_SUBST([REPLACE_STRTOUL])
+  REPLACE_STRTOULL=0;        AC_SUBST([REPLACE_STRTOULL])
   REPLACE_UNSETENV=0;        AC_SUBST([REPLACE_UNSETENV])
   REPLACE_WCTOMB=0;          AC_SUBST([REPLACE_WCTOMB])
 ])
diff --git a/m4/threadlib.m4 b/m4/threadlib.m4
index 20b383a88..8fc3dfd1f 100644
--- a/m4/threadlib.m4
+++ b/m4/threadlib.m4
@@ -1,4 +1,4 @@
-# threadlib.m4 serial 29
+# threadlib.m4 serial 30
 dnl Copyright (C) 2005-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -126,7 +126,7 @@ int main ()
      case "$gl_cv_have_weak" in
        *yes)
          case "$host_os" in
-           freebsd* | dragonfly*)
+           freebsd* | dragonfly* | midnightbsd*)
              : > conftest1.c
              $CC $CPPFLAGS $CFLAGS $LDFLAGS -fPIC -shared -o libempty.so conftest1.c -lpthread >&AS_MESSAGE_LOG_FD 2>&1
              cat <<EOF > conftest2.c
@@ -488,7 +488,7 @@ AC_DEFUN([gl_THREADLIB_BODY],
               LIBTHREAD= LTLIBTHREAD=
             else
               case "$host_os" in
-                freebsd* | dragonfly*)
+                freebsd* | dragonfly* | midnightbsd*)
                   if test "x$LIBTHREAD" != "x$LIBMULTITHREAD"; then
                     dnl If weak symbols can't tell whether pthread_create(), pthread_key_create()
                     dnl etc. will succeed, we need a runtime test.
diff --git a/m4/visibility.m4 b/m4/visibility.m4
index 6e4b46150..8f27a122d 100644
--- a/m4/visibility.m4
+++ b/m4/visibility.m4
@@ -1,4 +1,4 @@
-# visibility.m4 serial 6
+# visibility.m4 serial 7
 dnl Copyright (C) 2005, 2008, 2010-2021 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -58,6 +58,7 @@ AC_DEFUN([gl_VISIBILITY],
               extern __attribute__((__visibility__("default"))) int exportedvar;
               extern __attribute__((__visibility__("hidden"))) int hiddenfunc (void);
               extern __attribute__((__visibility__("default"))) int exportedfunc (void);
+              void dummyfunc (void);
               void dummyfunc (void) {}
             ]],
             [[]])],
diff --git a/maint.mk b/maint.mk
index 934f23d56..ae3a8170a 100644
--- a/maint.mk
+++ b/maint.mk
@@ -64,7 +64,11 @@ VC_LIST = $(srcdir)/$(_build-aux)/vc-list-files -C $(srcdir)
 
 # You can override this variable in cfg.mk if your gnulib submodule lives
 # in a different location.
-gnulib_dir ?= $(srcdir)/gnulib
+gnulib_dir ?= $(shell if test -d $(srcdir)/gnulib; then \
+			echo $(srcdir)/gnulib; \
+		else \
+			echo ${GNULIB_SRCDIR}; \
+		fi)
 
 # You can override this variable in cfg.mk to set your own regexp
 # matching files to ignore.