updated gnulib

29 files changed, 192 insertions, 110 deletions

diff --git a/gl/Makefile.am b/gl/Makefile.am
index 1cafa23d65..a716f2a712 100644
--- a/gl/Makefile.am
+++ b/gl/Makefile.am
@@ -623,6 +623,7 @@ stddef.h: stddef.in.h $(top_builddir)/config.status
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_STDDEF_H''@|$(NEXT_STDDEF_H)|g' \
+	      -e 's|@''HAVE_MAX_ALIGN_T''@|$(HAVE_MAX_ALIGN_T)|g' \
 	      -e 's|@''HAVE_WCHAR_T''@|$(HAVE_WCHAR_T)|g' \
 	      -e 's|@''REPLACE_NULL''@|$(REPLACE_NULL)|g' \
 	      < $(srcdir)/stddef.in.h; \
diff --git a/gl/m4/extensions.m4 b/gl/m4/extensions.m4
index 37f55ca3d1..cf285ba273 100644
--- a/gl/m4/extensions.m4
+++ b/gl/m4/extensions.m4
@@ -68,6 +68,10 @@ dnl configure.ac when using autoheader 2.62.
 #ifndef _GNU_SOURCE
 # undef _GNU_SOURCE
 #endif
+/* Use GNU style printf and scanf.  */
+#ifndef __USE_MINGW_ANSI_STDIO
+# undef __USE_MINGW_ANSI_STDIO
+#endif
 /* Enable threading extensions on Solaris.  */
 #ifndef _POSIX_PTHREAD_SEMANTICS
 # undef _POSIX_PTHREAD_SEMANTICS
@@ -100,6 +104,7 @@ dnl configure.ac when using autoheader 2.62.
   AC_DEFINE([_ALL_SOURCE])
   AC_DEFINE([_DARWIN_C_SOURCE])
   AC_DEFINE([_GNU_SOURCE])
+  AC_DEFINE([__USE_MINGW_ANSI_STDIO])
   AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
   AC_DEFINE([_TANDEM_SOURCE])
   AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
diff --git a/gl/m4/extern-inline.m4 b/gl/m4/extern-inline.m4
index 7f1bb397c4..0edbe3c81c 100644
--- a/gl/m4/extern-inline.m4
+++ b/gl/m4/extern-inline.m4
@@ -74,6 +74,11 @@ AC_DEFUN([gl_EXTERN_INLINE],
 # define _GL_EXTERN_INLINE static _GL_UNUSED
 #endif
 
+/* In GCC, suppress bogus "no previous prototype for 'FOO'"
+   and "no previous declaration for 'FOO'" diagnostics,
+   when FOO is an inline function in the header; see
+   <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113> and
+   <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63877>.  */
 #if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
 # if defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__
 #  define _GL_INLINE_HEADER_CONST_PRAGMA
@@ -81,10 +86,6 @@ AC_DEFUN([gl_EXTERN_INLINE],
 #  define _GL_INLINE_HEADER_CONST_PRAGMA \
      _Pragma ("GCC diagnostic ignored \"-Wsuggest-attribute=const\"")
 # endif
-  /* Suppress GCC's bogus "no previous prototype for 'FOO'"
-     and "no previous declaration for 'FOO'"  diagnostics,
-     when FOO is an inline function in the header; see
-     <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>.  */
 # define _GL_INLINE_HEADER_BEGIN \
     _Pragma ("GCC diagnostic push") \
     _Pragma ("GCC diagnostic ignored \"-Wmissing-prototypes\"") \
diff --git a/gl/m4/gnulib-comp.m4 b/gl/m4/gnulib-comp.m4
index 613c7dea6c..981bca2f2c 100644
--- a/gl/m4/gnulib-comp.m4
+++ b/gl/m4/gnulib-comp.m4
@@ -366,7 +366,7 @@ AC_SUBST([LTALLOCA])
     gl_PREREQ_STRVERSCMP
   fi
   gl_STRING_MODULE_INDICATOR([strverscmp])
-  gl_HEADER_SYS_SOCKET
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
   AC_PROG_MKDIR_P
   gl_HEADER_SYS_STAT_H
   AC_PROG_MKDIR_P
diff --git a/gl/m4/iconv.m4 b/gl/m4/iconv.m4
index 4b29c5f2c2..4e37363156 100644
--- a/gl/m4/iconv.m4
+++ b/gl/m4/iconv.m4
@@ -1,4 +1,4 @@
-# iconv.m4 serial 18 (gettext-0.18.2)
+# iconv.m4 serial 19 (gettext-0.18.2)
 dnl Copyright (C) 2000-2002, 2007-2014 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -72,27 +72,33 @@ AC_DEFUN([AM_ICONV_LINK],
       if test $am_cv_lib_iconv = yes; then
         LIBS="$LIBS $LIBICONV"
       fi
-      AC_RUN_IFELSE(
-        [AC_LANG_SOURCE([[
+      am_cv_func_iconv_works=no
+      for ac_iconv_const in '' 'const'; do
+        AC_RUN_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[
 #include <iconv.h>
 #include <string.h>
-int main ()
-{
-  int result = 0;
+
+#ifndef ICONV_CONST
+# define ICONV_CONST $ac_iconv_const
+#endif
+             ]],
+             [[int result = 0;
   /* Test against AIX 5.1 bug: Failures are not distinguishable from successful
      returns.  */
   {
     iconv_t cd_utf8_to_88591 = iconv_open ("ISO8859-1", "UTF-8");
     if (cd_utf8_to_88591 != (iconv_t)(-1))
       {
-        static const char input[] = "\342\202\254"; /* EURO SIGN */
+        static ICONV_CONST char input[] = "\342\202\254"; /* EURO SIGN */
         char buf[10];
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = strlen (input);
         char *outptr = buf;
         size_t outbytesleft = sizeof (buf);
         size_t res = iconv (cd_utf8_to_88591,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if (res == 0)
           result |= 1;
@@ -105,14 +111,14 @@ int main ()
     iconv_t cd_ascii_to_88591 = iconv_open ("ISO8859-1", "646");
     if (cd_ascii_to_88591 != (iconv_t)(-1))
       {
-        static const char input[] = "\263";
+        static ICONV_CONST char input[] = "\263";
         char buf[10];
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = strlen (input);
         char *outptr = buf;
         size_t outbytesleft = sizeof (buf);
         size_t res = iconv (cd_ascii_to_88591,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if (res == 0)
           result |= 2;
@@ -124,14 +130,14 @@ int main ()
     iconv_t cd_88591_to_utf8 = iconv_open ("UTF-8", "ISO-8859-1");
     if (cd_88591_to_utf8 != (iconv_t)(-1))
       {
-        static const char input[] = "\304";
+        static ICONV_CONST char input[] = "\304";
         static char buf[2] = { (char)0xDE, (char)0xAD };
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = 1;
         char *outptr = buf;
         size_t outbytesleft = 1;
         size_t res = iconv (cd_88591_to_utf8,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if (res != (size_t)(-1) || outptr - buf > 1 || buf[1] != (char)0xAD)
           result |= 4;
@@ -144,14 +150,14 @@ int main ()
     iconv_t cd_88591_to_utf8 = iconv_open ("utf8", "iso88591");
     if (cd_88591_to_utf8 != (iconv_t)(-1))
       {
-        static const char input[] = "\304rger mit b\366sen B\374bchen ohne Augenma\337";
+        static ICONV_CONST char input[] = "\304rger mit b\366sen B\374bchen ohne Augenma\337";
         char buf[50];
-        const char *inptr = input;
+        ICONV_CONST char *inptr = input;
         size_t inbytesleft = strlen (input);
         char *outptr = buf;
         size_t outbytesleft = sizeof (buf);
         size_t res = iconv (cd_88591_to_utf8,
-                            (char **) &inptr, &inbytesleft,
+                            &inptr, &inbytesleft,
                             &outptr, &outbytesleft);
         if ((int)res > 0)
           result |= 8;
@@ -171,17 +177,14 @@ int main ()
       && iconv_open ("utf8", "eucJP") == (iconv_t)(-1))
     result |= 16;
   return result;
-}]])],
-        [am_cv_func_iconv_works=yes],
-        [am_cv_func_iconv_works=no],
-        [
-changequote(,)dnl
-         case "$host_os" in
-           aix* | hpux*) am_cv_func_iconv_works="guessing no" ;;
-           *)            am_cv_func_iconv_works="guessing yes" ;;
-         esac
-changequote([,])dnl
-        ])
+]])],
+          [am_cv_func_iconv_works=yes], ,
+          [case "$host_os" in
+             aix* | hpux*) am_cv_func_iconv_works="guessing no" ;;
+             *)            am_cv_func_iconv_works="guessing yes" ;;
+           esac])
+        test "$am_cv_func_iconv_works" = no || break
+      done
       LIBS="$am_save_LIBS"
     ])
     case "$am_cv_func_iconv_works" in
diff --git a/gl/m4/printf.m4 b/gl/m4/printf.m4
index 3d7b381efd..652fa1cdc1 100644
--- a/gl/m4/printf.m4
+++ b/gl/m4/printf.m4
@@ -328,7 +328,7 @@ int main ()
 # ifdef WORDS_BIGENDIAN
 #  define LDBL80_WORDS(exponent,manthi,mantlo) \
      { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
-       ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16),    \
+       ((unsigned int) (manthi) << 16) | ((unsigned int) (mantlo) >> 16),   \
        (unsigned int) (mantlo) << 16                                        \
      }
 # else
diff --git a/gl/m4/stdalign.m4 b/gl/m4/stdalign.m4
index 9efafe5c5b..f60257f16a 100644
--- a/gl/m4/stdalign.m4
+++ b/gl/m4/stdalign.m4
@@ -32,8 +32,12 @@ AC_DEFUN([gl_STDALIGN_H],
             /* Test _Alignas only on platforms where gnulib can help.  */
             #if \
                 ((defined __cplusplus && 201103 <= __cplusplus) \
-                 || __GNUC__ || __IBMC__ || __IBMCPP__ || __ICC \
-                 || 0x5110 <= __SUNPRO_C || 1300 <= _MSC_VER)
+                 || (defined __APPLE__ && defined __MACH__ \
+                     ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+                     : __GNUC__) \
+                 || __HP_cc || __HP_aCC || __IBMC__ || __IBMCPP__ \
+                 || __ICC || 0x5110 <= __SUNPRO_C \
+                 || 1300 <= _MSC_VER)
               struct alignas_test { char c; char alignas (8) alignas_8; };
               char test_alignas[offsetof (struct alignas_test, alignas_8) == 8
                                 ? 1 : -1];
diff --git a/gl/m4/stddef_h.m4 b/gl/m4/stddef_h.m4
index c555e29524..9659813bda 100644
--- a/gl/m4/stddef_h.m4
+++ b/gl/m4/stddef_h.m4
@@ -1,5 +1,5 @@
-dnl A placeholder for POSIX 2008 <stddef.h>, for platforms that have issues.
-# stddef_h.m4 serial 4
+dnl A placeholder for <stddef.h>, for platforms that have issues.
+# stddef_h.m4 serial 5
 dnl Copyright (C) 2009-2014 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -10,6 +10,9 @@ AC_DEFUN([gl_STDDEF_H],
   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
   STDDEF_H=
+  AC_CHECK_TYPE([max_align_t], [], [HAVE_MAX_ALIGN_T=0; STDDEF_H=stddef.h],
+    [[#include <stddef.h>
+    ]])
   if test $gt_cv_c_wchar_t = no; then
     HAVE_WCHAR_T=0
     STDDEF_H=stddef.h
@@ -43,5 +46,6 @@ AC_DEFUN([gl_STDDEF_H_DEFAULTS],
 [
   dnl Assume proper GNU behavior unless another module says otherwise.
   REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
+  HAVE_MAX_ALIGN_T=1;            AC_SUBST([HAVE_MAX_ALIGN_T])
   HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
 ])
diff --git a/gl/m4/stdio_h.m4 b/gl/m4/stdio_h.m4
index d15913a3ca..ef0dcc12d2 100644
--- a/gl/m4/stdio_h.m4
+++ b/gl/m4/stdio_h.m4
@@ -6,6 +6,9 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_STDIO_H],
 [
+  dnl For __USE_MINGW_ANSI_STDIO
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
   gl_NEXT_HEADERS([stdio.h])
 
diff --git a/gl/stdalign.in.h b/gl/stdalign.in.h
index 446b45ce60..44762b7de5 100644
--- a/gl/stdalign.in.h
+++ b/gl/stdalign.in.h
@@ -95,7 +95,10 @@
 #if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
 # if defined __cplusplus && 201103 <= __cplusplus
 #  define _Alignas(a) alignas (a)
-# elif (__GNUC__ || __HP_cc || __HP_aCC || __IBMC__ || __IBMCPP__ \
+# elif ((defined __APPLE__ && defined __MACH__                  \
+         ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__)                 \
+         : __GNUC__)                                            \
+        || __HP_cc || __HP_aCC || __IBMC__ || __IBMCPP__        \
         || __ICC || 0x5110 <= __SUNPRO_C)
 #  define _Alignas(a) __attribute__ ((__aligned__ (a)))
 # elif 1300 <= _MSC_VER
diff --git a/gl/stddef.in.h b/gl/stddef.in.h
index ec944fd2a0..f36feb9b43 100644
--- a/gl/stddef.in.h
+++ b/gl/stddef.in.h
@@ -39,7 +39,6 @@
 
 # if !(defined _@GUARD_PREFIX@_STDDEF_H && defined _GL_STDDEF_WINT_T)
 #  ifdef __need_wint_t
-#   undef _@GUARD_PREFIX@_STDDEF_H
 #   define _GL_STDDEF_WINT_T
 #  endif
 #  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
@@ -54,33 +53,45 @@
 
 #  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
 
-#  ifndef _@GUARD_PREFIX@_STDDEF_H
-#   define _@GUARD_PREFIX@_STDDEF_H
-
 /* On NetBSD 5.0, the definition of NULL lacks proper parentheses.  */
-#if @REPLACE_NULL@
-# undef NULL
-# ifdef __cplusplus
+#  if (@REPLACE_NULL@ \
+       && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _GL_STDDEF_WINT_T))
+#   undef NULL
+#   ifdef __cplusplus
    /* ISO C++ says that the macro NULL must expand to an integer constant
       expression, hence '((void *) 0)' is not allowed in C++.  */
-#  if __GNUG__ >= 3
+#    if __GNUG__ >= 3
     /* GNU C++ has a __null macro that behaves like an integer ('int' or
        'long') but has the same size as a pointer.  Use that, to avoid
        warnings.  */
-#   define NULL __null
-#  else
-#   define NULL 0L
+#     define NULL __null
+#    else
+#     define NULL 0L
+#    endif
+#   else
+#    define NULL ((void *) 0)
+#   endif
 #  endif
-# else
-#  define NULL ((void *) 0)
-# endif
-#endif
+
+#  ifndef _@GUARD_PREFIX@_STDDEF_H
+#   define _@GUARD_PREFIX@_STDDEF_H
 
 /* Some platforms lack wchar_t.  */
 #if !@HAVE_WCHAR_T@
 # define wchar_t int
 #endif
 
+/* Some platforms lack max_align_t.  */
+#if !@HAVE_MAX_ALIGN_T@
+typedef union
+{
+  char *__p;
+  double __d;
+  long double __ld;
+  long int __i;
+} max_align_t;
+#endif
+
 #  endif /* _@GUARD_PREFIX@_STDDEF_H */
 # endif /* _@GUARD_PREFIX@_STDDEF_H */
 #endif /* __need_XXX */
diff --git a/gl/tests/test-fcntl-h.c b/gl/tests/test-fcntl-h.c
index a86214ee4c..19e4fc53fd 100644
--- a/gl/tests/test-fcntl-h.c
+++ b/gl/tests/test-fcntl-h.c
@@ -111,7 +111,7 @@ main (void)
 #if O_RSYNC && O_RSYNC != O_DSYNC
     case O_RSYNC:
 #endif
-#if O_SYNC && O_SYNC != O_RSYNC
+#if O_SYNC && O_SYNC != O_DSYNC && O_SYNC != O_RSYNC
     case O_SYNC:
 #endif
 #if O_TTY_INIT
diff --git a/gl/tests/test-stddef.c b/gl/tests/test-stddef.c
index d5d887eb23..0b8649d126 100644
--- a/gl/tests/test-stddef.c
+++ b/gl/tests/test-stddef.c
@@ -19,13 +19,14 @@
 #include <config.h>
 
 #include <stddef.h>
-
+#include <stdalign.h>
 #include "verify.h"
 
 /* Check that appropriate types are defined.  */
 wchar_t a = 'c';
 ptrdiff_t b = 1;
 size_t c = 2;
+max_align_t x;
 
 /* Check that NULL can be passed through varargs as a pointer type,
    per POSIX 2008.  */
@@ -45,6 +46,16 @@ verify (sizeof (offsetof (struct d, e)) == sizeof (size_t));
 verify (offsetof (struct d, e) < -1); /* Must be unsigned.  */
 verify (offsetof (struct d, f) == 1);
 
+/* Check max_align_t's alignment.  */
+verify (alignof (double) <= alignof (max_align_t));
+verify (alignof (int) <= alignof (max_align_t));
+verify (alignof (long double) <= alignof (max_align_t));
+verify (alignof (long int) <= alignof (max_align_t));
+verify (alignof (ptrdiff_t) <= alignof (max_align_t));
+verify (alignof (size_t) <= alignof (max_align_t));
+verify (alignof (wchar_t) <= alignof (max_align_t));
+verify (alignof (struct d) <= alignof (max_align_t));
+
 int
 main (void)
 {
diff --git a/gl/unistd.in.h b/gl/unistd.in.h
index 1aae789afe..0c863f3305 100644
--- a/gl/unistd.in.h
+++ b/gl/unistd.in.h
@@ -401,13 +401,12 @@ _GL_WARN_ON_USE (dup3, "dup3 is unportable - "
 /* Set of environment variables and values.  An array of strings of the form
    "VARIABLE=VALUE", terminated with a NULL.  */
 #  if defined __APPLE__ && defined __MACH__
-#   include "TargetConditionals.h"
-#   if !defined(TARGET_OS_IPHONE) && !defined(TARGET_IPHONE_SIMULATOR)
-#     define APPLE_USE_CRT_EXTERNS
+#   include <TargetConditionals.h>
+#   if !TARGET_OS_IPHONE && !TARGET_IPHONE_SIMULATOR
+#    define _GL_USE_CRT_EXTERNS
 #   endif
 #  endif
-#
-#  ifdef APPLE_USE_CRT_EXTERNS
+#  ifdef _GL_USE_CRT_EXTERNS
 #   include <crt_externs.h>
 #   define environ (*_NSGetEnviron ())
 #  else
diff --git a/gl/vasnprintf.c b/gl/vasnprintf.c
index ab49b66315..3137aeb803 100644
--- a/gl/vasnprintf.c
+++ b/gl/vasnprintf.c
@@ -5179,18 +5179,21 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                         /* SNPRINTF or sprintf failed.  Save and use the errno
                            that it has set, if any.  */
                         int saved_errno = errno;
+                        if (saved_errno == 0)
+                          {
+                            if (dp->conversion == 'c' || dp->conversion == 's')
+                              saved_errno = EILSEQ;
+                            else
+                              saved_errno = EINVAL;
+                          }
 
                         if (!(result == resultbuf || result == NULL))
                           free (result);
                         if (buf_malloced != NULL)
                           free (buf_malloced);
                         CLEANUP ();
-                        errno =
-                          (saved_errno != 0
-                           ? saved_errno
-                           : (dp->conversion == 'c' || dp->conversion == 's'
-                              ? EILSEQ
-                              : EINVAL));
+
+                        errno = saved_errno;
                         return NULL;
                       }
 
diff --git a/src/gl/Makefile.am b/src/gl/Makefile.am
index 7e42d126ea..2d31405d9d 100644
--- a/src/gl/Makefile.am
+++ b/src/gl/Makefile.am
@@ -860,6 +860,7 @@ stddef.h: stddef.in.h $(top_builddir)/config.status
 	      -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
 	      -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
 	      -e 's|@''NEXT_STDDEF_H''@|$(NEXT_STDDEF_H)|g' \
+	      -e 's|@''HAVE_MAX_ALIGN_T''@|$(HAVE_MAX_ALIGN_T)|g' \
 	      -e 's|@''HAVE_WCHAR_T''@|$(HAVE_WCHAR_T)|g' \
 	      -e 's|@''REPLACE_NULL''@|$(REPLACE_NULL)|g' \
 	      < $(srcdir)/stddef.in.h; \
diff --git a/src/gl/m4/extensions.m4 b/src/gl/m4/extensions.m4
index 37f55ca3d1..cf285ba273 100644
--- a/src/gl/m4/extensions.m4
+++ b/src/gl/m4/extensions.m4
@@ -68,6 +68,10 @@ dnl configure.ac when using autoheader 2.62.
 #ifndef _GNU_SOURCE
 # undef _GNU_SOURCE
 #endif
+/* Use GNU style printf and scanf.  */
+#ifndef __USE_MINGW_ANSI_STDIO
+# undef __USE_MINGW_ANSI_STDIO
+#endif
 /* Enable threading extensions on Solaris.  */
 #ifndef _POSIX_PTHREAD_SEMANTICS
 # undef _POSIX_PTHREAD_SEMANTICS
@@ -100,6 +104,7 @@ dnl configure.ac when using autoheader 2.62.
   AC_DEFINE([_ALL_SOURCE])
   AC_DEFINE([_DARWIN_C_SOURCE])
   AC_DEFINE([_GNU_SOURCE])
+  AC_DEFINE([__USE_MINGW_ANSI_STDIO])
   AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
   AC_DEFINE([_TANDEM_SOURCE])
   AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
diff --git a/src/gl/m4/extern-inline.m4 b/src/gl/m4/extern-inline.m4
index 7f1bb397c4..0edbe3c81c 100644
--- a/src/gl/m4/extern-inline.m4
+++ b/src/gl/m4/extern-inline.m4
@@ -74,6 +74,11 @@ AC_DEFUN([gl_EXTERN_INLINE],
 # define _GL_EXTERN_INLINE static _GL_UNUSED
 #endif
 
+/* In GCC, suppress bogus "no previous prototype for 'FOO'"
+   and "no previous declaration for 'FOO'" diagnostics,
+   when FOO is an inline function in the header; see
+   <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113> and
+   <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63877>.  */
 #if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
 # if defined __GNUC_STDC_INLINE__ && __GNUC_STDC_INLINE__
 #  define _GL_INLINE_HEADER_CONST_PRAGMA
@@ -81,10 +86,6 @@ AC_DEFUN([gl_EXTERN_INLINE],
 #  define _GL_INLINE_HEADER_CONST_PRAGMA \
      _Pragma ("GCC diagnostic ignored \"-Wsuggest-attribute=const\"")
 # endif
-  /* Suppress GCC's bogus "no previous prototype for 'FOO'"
-     and "no previous declaration for 'FOO'"  diagnostics,
-     when FOO is an inline function in the header; see
-     <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54113>.  */
 # define _GL_INLINE_HEADER_BEGIN \
     _Pragma ("GCC diagnostic push") \
     _Pragma ("GCC diagnostic ignored \"-Wmissing-prototypes\"") \
diff --git a/src/gl/m4/gnulib-comp.m4 b/src/gl/m4/gnulib-comp.m4
index edd03a71fd..8dae6a8d3e 100644
--- a/src/gl/m4/gnulib-comp.m4
+++ b/src/gl/m4/gnulib-comp.m4
@@ -387,8 +387,8 @@ AC_SUBST([LTALLOCA])
     SYS_IOCTL_H_HAVE_WINSOCK2_H_AND_USE_SOCKETS=1
   fi
   gl_SYS_SOCKET_MODULE_INDICATOR([socket])
-  gl_SOCKETLIB
-  gl_SOCKETS
+  AC_REQUIRE([gl_SOCKETLIB])
+  AC_REQUIRE([gl_SOCKETS])
   gl_TYPE_SOCKLEN_T
   gt_TYPE_SSIZE_T
   gl_STDALIGN_H
@@ -418,7 +418,7 @@ AC_SUBST([LTALLOCA])
   gl_HEADER_STRING_H
   gl_HEADER_SYS_SELECT
   AC_PROG_MKDIR_P
-  gl_HEADER_SYS_SOCKET
+  AC_REQUIRE([gl_HEADER_SYS_SOCKET])
   AC_PROG_MKDIR_P
   gl_HEADER_SYS_STAT_H
   AC_PROG_MKDIR_P
diff --git a/src/gl/m4/printf.m4 b/src/gl/m4/printf.m4
index 3d7b381efd..652fa1cdc1 100644
--- a/src/gl/m4/printf.m4
+++ b/src/gl/m4/printf.m4
@@ -328,7 +328,7 @@ int main ()
 # ifdef WORDS_BIGENDIAN
 #  define LDBL80_WORDS(exponent,manthi,mantlo) \
      { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
-       ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16),    \
+       ((unsigned int) (manthi) << 16) | ((unsigned int) (mantlo) >> 16),   \
        (unsigned int) (mantlo) << 16                                        \
      }
 # else
diff --git a/src/gl/m4/stdalign.m4 b/src/gl/m4/stdalign.m4
index 9efafe5c5b..f60257f16a 100644
--- a/src/gl/m4/stdalign.m4
+++ b/src/gl/m4/stdalign.m4
@@ -32,8 +32,12 @@ AC_DEFUN([gl_STDALIGN_H],
             /* Test _Alignas only on platforms where gnulib can help.  */
             #if \
                 ((defined __cplusplus && 201103 <= __cplusplus) \
-                 || __GNUC__ || __IBMC__ || __IBMCPP__ || __ICC \
-                 || 0x5110 <= __SUNPRO_C || 1300 <= _MSC_VER)
+                 || (defined __APPLE__ && defined __MACH__ \
+                     ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+                     : __GNUC__) \
+                 || __HP_cc || __HP_aCC || __IBMC__ || __IBMCPP__ \
+                 || __ICC || 0x5110 <= __SUNPRO_C \
+                 || 1300 <= _MSC_VER)
               struct alignas_test { char c; char alignas (8) alignas_8; };
               char test_alignas[offsetof (struct alignas_test, alignas_8) == 8
                                 ? 1 : -1];
diff --git a/src/gl/m4/stddef_h.m4 b/src/gl/m4/stddef_h.m4
index c555e29524..9659813bda 100644
--- a/src/gl/m4/stddef_h.m4
+++ b/src/gl/m4/stddef_h.m4
@@ -1,5 +1,5 @@
-dnl A placeholder for POSIX 2008 <stddef.h>, for platforms that have issues.
-# stddef_h.m4 serial 4
+dnl A placeholder for <stddef.h>, for platforms that have issues.
+# stddef_h.m4 serial 5
 dnl Copyright (C) 2009-2014 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -10,6 +10,9 @@ AC_DEFUN([gl_STDDEF_H],
   AC_REQUIRE([gl_STDDEF_H_DEFAULTS])
   AC_REQUIRE([gt_TYPE_WCHAR_T])
   STDDEF_H=
+  AC_CHECK_TYPE([max_align_t], [], [HAVE_MAX_ALIGN_T=0; STDDEF_H=stddef.h],
+    [[#include <stddef.h>
+    ]])
   if test $gt_cv_c_wchar_t = no; then
     HAVE_WCHAR_T=0
     STDDEF_H=stddef.h
@@ -43,5 +46,6 @@ AC_DEFUN([gl_STDDEF_H_DEFAULTS],
 [
   dnl Assume proper GNU behavior unless another module says otherwise.
   REPLACE_NULL=0;                AC_SUBST([REPLACE_NULL])
+  HAVE_MAX_ALIGN_T=1;            AC_SUBST([HAVE_MAX_ALIGN_T])
   HAVE_WCHAR_T=1;                AC_SUBST([HAVE_WCHAR_T])
 ])
diff --git a/src/gl/m4/stdio_h.m4 b/src/gl/m4/stdio_h.m4
index d15913a3ca..ef0dcc12d2 100644
--- a/src/gl/m4/stdio_h.m4
+++ b/src/gl/m4/stdio_h.m4
@@ -6,6 +6,9 @@ dnl with or without modifications, as long as this notice is preserved.
 
 AC_DEFUN([gl_STDIO_H],
 [
+  dnl For __USE_MINGW_ANSI_STDIO
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
   gl_NEXT_HEADERS([stdio.h])
 
diff --git a/src/gl/parse-datetime.y b/src/gl/parse-datetime.y
index 52e6a0c215..72d6c38600 100644
--- a/src/gl/parse-datetime.y
+++ b/src/gl/parse-datetime.y
@@ -1031,7 +1031,7 @@ lookup_word (parser_control const *pc, char *word)
 }
 
 static int
-yylex (YYSTYPE *lvalp, parser_control *pc)
+yylex (union YYSTYPE *lvalp, parser_control *pc)
 {
   unsigned char c;
   size_t count;
diff --git a/src/gl/stdalign.in.h b/src/gl/stdalign.in.h
index dcaab55b57..413936df78 100644
--- a/src/gl/stdalign.in.h
+++ b/src/gl/stdalign.in.h
@@ -95,7 +95,10 @@
 #if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
 # if defined __cplusplus && 201103 <= __cplusplus
 #  define _Alignas(a) alignas (a)
-# elif (__GNUC__ || __HP_cc || __HP_aCC || __IBMC__ || __IBMCPP__ \
+# elif ((defined __APPLE__ && defined __MACH__                  \
+         ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__)                 \
+         : __GNUC__)                                            \
+        || __HP_cc || __HP_aCC || __IBMC__ || __IBMCPP__        \
         || __ICC || 0x5110 <= __SUNPRO_C)
 #  define _Alignas(a) __attribute__ ((__aligned__ (a)))
 # elif 1300 <= _MSC_VER
diff --git a/src/gl/stddef.in.h b/src/gl/stddef.in.h
index f5c0e05655..9924a327fc 100644
--- a/src/gl/stddef.in.h
+++ b/src/gl/stddef.in.h
@@ -39,7 +39,6 @@
 
 # if !(defined _@GUARD_PREFIX@_STDDEF_H && defined _GL_STDDEF_WINT_T)
 #  ifdef __need_wint_t
-#   undef _@GUARD_PREFIX@_STDDEF_H
 #   define _GL_STDDEF_WINT_T
 #  endif
 #  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
@@ -54,33 +53,45 @@
 
 #  @INCLUDE_NEXT@ @NEXT_STDDEF_H@
 
-#  ifndef _@GUARD_PREFIX@_STDDEF_H
-#   define _@GUARD_PREFIX@_STDDEF_H
-
 /* On NetBSD 5.0, the definition of NULL lacks proper parentheses.  */
-#if @REPLACE_NULL@
-# undef NULL
-# ifdef __cplusplus
+#  if (@REPLACE_NULL@ \
+       && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _GL_STDDEF_WINT_T))
+#   undef NULL
+#   ifdef __cplusplus
    /* ISO C++ says that the macro NULL must expand to an integer constant
       expression, hence '((void *) 0)' is not allowed in C++.  */
-#  if __GNUG__ >= 3
+#    if __GNUG__ >= 3
     /* GNU C++ has a __null macro that behaves like an integer ('int' or
        'long') but has the same size as a pointer.  Use that, to avoid
        warnings.  */
-#   define NULL __null
-#  else
-#   define NULL 0L
+#     define NULL __null
+#    else
+#     define NULL 0L
+#    endif
+#   else
+#    define NULL ((void *) 0)
+#   endif
 #  endif
-# else
-#  define NULL ((void *) 0)
-# endif
-#endif
+
+#  ifndef _@GUARD_PREFIX@_STDDEF_H
+#   define _@GUARD_PREFIX@_STDDEF_H
 
 /* Some platforms lack wchar_t.  */
 #if !@HAVE_WCHAR_T@
 # define wchar_t int
 #endif
 
+/* Some platforms lack max_align_t.  */
+#if !@HAVE_MAX_ALIGN_T@
+typedef union
+{
+  char *__p;
+  double __d;
+  long double __ld;
+  long int __i;
+} max_align_t;
+#endif
+
 #  endif /* _@GUARD_PREFIX@_STDDEF_H */
 # endif /* _@GUARD_PREFIX@_STDDEF_H */
 #endif /* __need_XXX */
diff --git a/src/gl/timespec.h b/src/gl/timespec.h
index 872cbb76e3..dfc1277a71 100644
--- a/src/gl/timespec.h
+++ b/src/gl/timespec.h
@@ -74,7 +74,7 @@ make_timespec (time_t s, long int ns)
 
    The (int) cast avoids a gcc -Wconversion warning.  */
 
-_GL_TIMESPEC_INLINE int
+_GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
 timespec_cmp (struct timespec a, struct timespec b)
 {
   return (a.tv_sec < b.tv_sec ? -1
@@ -84,7 +84,7 @@ timespec_cmp (struct timespec a, struct timespec b)
 
 /* Return -1, 0, 1, depending on the sign of A.  A.tv_nsec must be
    nonnegative.  */
-_GL_TIMESPEC_INLINE int
+_GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
 timespec_sign (struct timespec a)
 {
   return a.tv_sec < 0 ? -1 : a.tv_sec || a.tv_nsec;
diff --git a/src/gl/unistd.in.h b/src/gl/unistd.in.h
index 4e70ba464d..dda0b4d104 100644
--- a/src/gl/unistd.in.h
+++ b/src/gl/unistd.in.h
@@ -401,13 +401,12 @@ _GL_WARN_ON_USE (dup3, "dup3 is unportable - "
 /* Set of environment variables and values.  An array of strings of the form
    "VARIABLE=VALUE", terminated with a NULL.  */
 #  if defined __APPLE__ && defined __MACH__
-#   include "TargetConditionals.h"
-#   if !defined(TARGET_OS_IPHONE) && !defined(TARGET_IPHONE_SIMULATOR)
-#     define APPLE_USE_CRT_EXTERNS
+#   include <TargetConditionals.h>
+#   if !TARGET_OS_IPHONE && !TARGET_IPHONE_SIMULATOR
+#    define _GL_USE_CRT_EXTERNS
 #   endif
 #  endif
-#
-#  ifdef APPLE_USE_CRT_EXTERNS
+#  ifdef _GL_USE_CRT_EXTERNS
 #   include <crt_externs.h>
 #   define environ (*_NSGetEnviron ())
 #  else
diff --git a/src/gl/vasnprintf.c b/src/gl/vasnprintf.c
index ec7302a96e..6b30cebdff 100644
--- a/src/gl/vasnprintf.c
+++ b/src/gl/vasnprintf.c
@@ -5179,18 +5179,21 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                         /* SNPRINTF or sprintf failed.  Save and use the errno
                            that it has set, if any.  */
                         int saved_errno = errno;
+                        if (saved_errno == 0)
+                          {
+                            if (dp->conversion == 'c' || dp->conversion == 's')
+                              saved_errno = EILSEQ;
+                            else
+                              saved_errno = EINVAL;
+                          }
 
                         if (!(result == resultbuf || result == NULL))
                           free (result);
                         if (buf_malloced != NULL)
                           free (buf_malloced);
                         CLEANUP ();
-                        errno =
-                          (saved_errno != 0
-                           ? saved_errno
-                           : (dp->conversion == 'c' || dp->conversion == 's'
-                              ? EILSEQ
-                              : EINVAL));
+
+                        errno = saved_errno;
                         return NULL;
                       }