Support compiling without -loldnames on native Windows.

* m4/gnulib-common.m4 (GL_MDA_DEFINES, _GL_MDA_DEFINES): New macros.
* m4/chown.m4 (AC_FUNC_CHOWN): In the test programs, use GL_MDA_DEFINES.
(gl_FUNC_CHOWN, gl_FUNC_CHOWN_FOLLOWS_SYMLINK): Likewise.
* m4/dup.m4 (gl_FUNC_DUP): Likewise.
* m4/dup2.m4 (gl_FUNC_DUP2): Likewise.
* m4/fchdir.m4 (gl_FUNC_FCHDIR): Likewise.
* m4/fchmodat.m4 (gl_FUNC_FCHMODAT): Likewise.
* m4/fchownat.m4 (gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG): Likewise.
* m4/fcntl-o.m4 (gl_FCNTL_O_FLAGS): Likewise.
* m4/fcntl.m4 (gl_FUNC_FCNTL): Likewise.
* m4/fdopen.m4 (gl_FUNC_FDOPEN): Likewise.
* m4/fdopendir.m4 (gl_FUNC_FDOPENDIR): Likewise.
* m4/fflush.m4 (gl_FUNC_FFLUSH_STDIN): Likewise.
* m4/fopen.m4 (gl_FUNC_FOPEN_GNU): Likewise.
* m4/freopen.m4 (gl_FUNC_FREOPEN): Likewise.
* m4/futimens.m4 (gl_FUNC_FUTIMENS): Likewise.
* m4/getcwd-abort-bug.m4 (gl_FUNC_GETCWD_ABORT_BUG): Likewise.
* m4/getcwd-path-max.m4 (gl_FUNC_GETCWD_PATH_MAX): Likewise.
* m4/getcwd.m4 (gl_FUNC_GETCWD_NULL, gl_FUNC_GETCWD_SIGNATURE):
Likewise.
* m4/getdtablesize.m4 (gl_FUNC_GETDTABLESIZE): Likewise.
* m4/linkat.m4 (gl_FUNC_LINKAT): Likewise.
* m4/lseek.m4 (gl_FUNC_LSEEK): Likewise.
* m4/mkdir.m4 (gl_FUNC_MKDIR): Likewise.
* m4/mkstemp.m4 (gl_FUNC_MKSTEMP): Likewise.
* m4/mktime.m4 (gl_FUNC_MKTIME_WORKS): Likewise.
* m4/open-slash.m4 (gl_OPEN_TRAILING_SLASH_BUG): Likewise.
* m4/poll.m4 (gl_FUNC_POLL): Likewise.
* m4/posix_spawn.m4 (gl_POSIX_SPAWN_WORKS): Likewise.
* m4/pread.m4 (gl_FUNC_PREAD): Likewise.
* m4/pselect.m4 (gl_FUNC_PSELECT): Likewise.
* m4/pthread_sigmask.m4 (gl_FUNC_PTHREAD_SIGMASK): Likewise.
* m4/ptsname_r.m4 (gl_PREREQ_PTSNAME_R): Likewise.
* m4/putenv.m4 (gl_FUNC_PUTENV): Likewise.
* m4/pwrite.m4 (gl_FUNC_PWRITE): Likewise.
* m4/rename.m4 (gl_FUNC_RENAME): Likewise.
* m4/rmdir-errno.m4 (gl_FUNC_RMDIR_NOTEMPTY): Likewise.
* m4/rmdir.m4 (gl_FUNC_RMDIR): Likewise.
* m4/select.m4 (gl_FUNC_SELECT): Likewise.
* m4/setenv.m4 (gl_FUNC_UNSETENV): Likewise.
* m4/strncat.m4 (gl_FUNC_STRNCAT): Likewise.
* m4/ttyname_r.m4 (gl_FUNC_TTYNAME_R): Likewise.
* m4/unlink-busy.m4 (gl_FUNC_UNLINK_BUSY_TEXT): Likewise.
* m4/unlink.m4 (gl_FUNC_UNLINK): Likewise.
* m4/utimens.m4 (gl_UTIMENS): Likewise.
* m4/utimensat.m4 (gl_FUNC_UTIMENSAT): Likewise.
* m4/utimes.m4 (gl_FUNC_UTIMES): Likewise.
* m4/canonicalize.m4 (gl_CANONICALIZE_LGPL): On native Windows, don't
test for getcwd.
* m4/utime.m4 (gl_FUNC_UTIME): On native Windows, don't test for utime.
* m4/wcsdup.m4 (gl_FUNC_WCSDUP): To test for wcsdup, use a test program
with GL_MDA_DEFINES.
* lib/c++defs.h (_GL_CXXALIAS_MDA): New macro.
* lib/fcntl.in.h (creat, open):  On native Windows, use the underscore-
prefixed symbol.
* lib/search.in.h (lfind, lsearch): Likewise.
* lib/stdio.in.h (fcloseall, fdopen, fileno, getw, putw, tempnam):
Likewise.
* lib/stdlib.in.h (ecvt, fcvt, gcvt, mktemp, putenv): Likewise.
* lib/string.in.h (memccpy, strdup): Likewise.
* lib/sys_stat.in.h (chmod, umask): Likewise.
* lib/time.in.h (tzset): Likewise.
* lib/unistd.in.h (access, chdir, close, dup, dup2, execl, execle,
execlp, execv, execve, execvp, execvpe, getcwd, getpid, isatty, lseek,
read, rmdir, swab, unlink, write): Likewise.
* lib/utime.in.h (utime): Likewise.
* lib/wchar.in.h (wcsdup): Likewise.
* lib/math.in.h (j0, j1, jn, y0, y1, yn):  Likewise.
(isfinite, isinf, isnan, signbit): On native Windows, don't define as an
rpl_-prefixed macro.
* lib/canonicalize-lgpl.c (__getcwd): On native Windows, use _getcwd.
* lib/close.c (close_nothrow): On native Windows, use _close.
* lib/creat.c (orig_creat): On native Windows, use _creat.
* lib/dup.c (dup_nothrow): On native Windows, use _dup.
* lib/dup2.c (dup2_nothrow): Use _dup2.
* lib/fdopen.c (fdopen_nothrow): On native Windows, use _fdopen.
* lib/getcwd-lgpl.c: On native Windows, use _getcwd.
* lib/getcwd.c (getcwd_nothrow): Use _getcwd also on mingw.
* lib/open.c (orig_open): On native Windows, use _open.
* lib/read.c (read_nothrow): Use _read.
* lib/rmdir.c: On native Windows, use _rmdir.
* lib/unlink.c: On native Windows, use _unlink.
* lib/write.c (write_nothrow): Use _write.
* lib/sys_select.in.h (close): With clang, don't attach a warning on an
undefined symbol.
* lib/sys_socket.in.h (close): Likewise.
* lib/sys_time.in.h (close): Likewise.
* tests/test-spawn-pipe-child.c: On native Windows, use _fdopen.

48 files changed, 374 insertions, 219 deletions

diff --git a/m4/canonicalize.m4 b/m4/canonicalize.m4
index bdc5c8f71a..de64cf7ab0 100644
--- a/m4/canonicalize.m4
+++ b/m4/canonicalize.m4
@@ -1,4 +1,4 @@
-# canonicalize.m4 serial 31
+# canonicalize.m4 serial 32
 
 dnl Copyright (C) 2003-2007, 2009-2020 Free Software Foundation, Inc.
 
@@ -56,7 +56,16 @@ AC_DEFUN([gl_CANONICALIZE_LGPL],
 AC_DEFUN([gl_CANONICALIZE_LGPL_SEPARATE],
 [
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
-  AC_CHECK_FUNCS_ONCE([canonicalize_file_name getcwd readlink])
+  AC_CHECK_FUNCS_ONCE([canonicalize_file_name readlink])
+
+  dnl On native Windows, we use _getcwd(), regardless whether getcwd() is
+  dnl available through the linker option '-loldnames'.
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  case "$host_os" in
+    mingw*) ;;
+    *)      AC_CHECK_FUNCS([getcwd]) ;;
+  esac
+
   AC_REQUIRE([gl_DOUBLE_SLASH_ROOT])
   AC_REQUIRE([gl_FUNC_REALPATH_WORKS])
   AC_CHECK_HEADERS_ONCE([sys/param.h])
diff --git a/m4/chown.m4 b/m4/chown.m4
index 3638187aac..e28750395d 100644
--- a/m4/chown.m4
+++ b/m4/chown.m4
@@ -1,4 +1,4 @@
-# serial 34
+# serial 35
 # Determine whether we need the chown wrapper.
 
 dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009-2020 Free Software
@@ -27,7 +27,7 @@ AC_DEFUN([AC_FUNC_CHOWN],
        [AC_LANG_PROGRAM(
           [AC_INCLUDES_DEFAULT
            [#include <fcntl.h>
-          ]],
+          ]GL_MDA_DEFINES],
           [[
             char *f = "conftest.chown";
             struct stat before, after;
@@ -104,7 +104,8 @@ AC_DEFUN_ONCE([gl_FUNC_CHOWN],
 #include <unistd.h>
 #include <stdlib.h>
 #include <errno.h>
-]], [[    if (symlink ("conftest.file", "conftest.link")) return 1;
+]GL_MDA_DEFINES],
+        [[if (symlink ("conftest.file", "conftest.link")) return 1;
           if (chown ("conftest.link/", getuid (), getgid ()) == 0) return 2;
         ]])],
         [gl_cv_func_chown_slash_works=yes],
@@ -137,7 +138,8 @@ AC_DEFUN_ONCE([gl_FUNC_CHOWN],
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
-]], [[    struct stat st1, st2;
+]GL_MDA_DEFINES],
+        [[struct stat st1, st2;
           if (close (creat ("conftest.file", 0600))) return 1;
           if (stat ("conftest.file", &st1)) return 2;
           sleep (1);
@@ -179,7 +181,7 @@ AC_DEFUN_ONCE([gl_FUNC_CHOWN_FOLLOWS_SYMLINK],
 #include <unistd.h>
 #include <stdlib.h>
 #include <errno.h>
-
+]GL_MDA_DEFINES[
         int
         main ()
         {
diff --git a/m4/dup.m4 b/m4/dup.m4
index 1bf02347af..892de99f4a 100644
--- a/m4/dup.m4
+++ b/m4/dup.m4
@@ -1,4 +1,4 @@
-# dup.m4 serial 6
+# dup.m4 serial 7
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -26,7 +26,8 @@ AC_DEFUN([gl_FUNC_DUP],
     [AC_RUN_IFELSE(
       [AC_LANG_PROGRAM([[#include <unistd.h>
                          #include <fcntl.h>
-                         #include <errno.h>]],
+                         #include <errno.h>
+                       ]GL_MDA_DEFINES],
          [[/* On OS/2 kLIBC, dup does not work on a directory fd.  */
            int fd = open (".", O_RDONLY);
            return fd < 0 ? 1 : dup (fd) < 0 ? 2 : 0;
diff --git a/m4/dup2.m4 b/m4/dup2.m4
index 462bfd0e52..a82798d6bb 100644
--- a/m4/dup2.m4
+++ b/m4/dup2.m4
@@ -1,4 +1,4 @@
-#serial 26
+#serial 27
 dnl Copyright (C) 2002, 2005, 2007, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -16,6 +16,7 @@ AC_DEFUN([gl_FUNC_DUP2],
            #include <limits.h>
            #include <sys/resource.h>
            #include <unistd.h>
+           ]GL_MDA_DEFINES[
            #ifndef RLIM_SAVED_CUR
            # define RLIM_SAVED_CUR RLIM_INFINITY
            #endif
diff --git a/m4/fchdir.m4 b/m4/fchdir.m4
index dc2ba25183..8e894e05ca 100644
--- a/m4/fchdir.m4
+++ b/m4/fchdir.m4
@@ -1,4 +1,4 @@
-# fchdir.m4 serial 25
+# fchdir.m4 serial 26
 dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -26,21 +26,24 @@ AC_DEFUN([gl_FUNC_FCHDIR],
     dnl fstatat, since no platform has fstatat but lacks fchdir.
     AC_CACHE_CHECK([whether open can visit directories],
       [gl_cv_func_open_directory_works],
-      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <fcntl.h>
-]], [return open(".", O_RDONLY) < 0;])],
-        [gl_cv_func_open_directory_works=yes],
-        [gl_cv_func_open_directory_works=no],
-        [case "$host_os" in
-                            # Guess yes on Linux systems.
-           linux-* | linux) gl_cv_func_open_directory_works="guessing yes" ;;
-                            # Guess yes on glibc systems.
-           *-gnu* | gnu*)   gl_cv_func_open_directory_works="guessing yes" ;;
-                            # Guess no on native Windows.
-           mingw*)          gl_cv_func_open_directory_works="guessing no" ;;
-                            # If we don't know, obey --enable-cross-guesses.
-           *)               gl_cv_func_open_directory_works="$gl_cross_guess_normal" ;;
-         esac
-        ])])
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <fcntl.h>
+            ]GL_MDA_DEFINES],
+            [[return open(".", O_RDONLY) < 0;]])],
+         [gl_cv_func_open_directory_works=yes],
+         [gl_cv_func_open_directory_works=no],
+         [case "$host_os" in
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_open_directory_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_open_directory_works="guessing yes" ;;
+                             # Guess no on native Windows.
+            mingw*)          gl_cv_func_open_directory_works="guessing no" ;;
+                             # If we don't know, obey --enable-cross-guesses.
+            *)               gl_cv_func_open_directory_works="$gl_cross_guess_normal" ;;
+          esac
+         ])])
     case "$gl_cv_func_open_directory_works" in
       *yes) ;;
       *)
diff --git a/m4/fchmodat.m4 b/m4/fchmodat.m4
index e3f2f04816..cf5c87999c 100644
--- a/m4/fchmodat.m4
+++ b/m4/fchmodat.m4
@@ -1,4 +1,4 @@
-# fchmodat.m4 serial 4
+# fchmodat.m4 serial 5
 dnl Copyright (C) 2004-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -40,7 +40,7 @@ AC_DEFUN([gl_FUNC_FCHMODAT],
               #ifndef S_IRWXO
                #define S_IRWXO 0007
               #endif
-            ]],
+            ]GL_MDA_DEFINES],
             [[
               int permissive = S_IRWXU | S_IRWXG | S_IRWXO;
               int desired = S_IRUSR | S_IWUSR;
diff --git a/m4/fchownat.m4 b/m4/fchownat.m4
index 0a5d637030..ea49906a54 100644
--- a/m4/fchownat.m4
+++ b/m4/fchownat.m4
@@ -1,4 +1,4 @@
-# fchownat.m4 serial 6
+# fchownat.m4 serial 7
 dnl Copyright (C) 2004-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -90,7 +90,7 @@ AC_DEFUN([gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG],
             #include <fcntl.h>
             /* Android 4.3 declares fchownat() in <sys/stat.h> instead.  */
             #include <sys/stat.h>
-          ]],
+          ]GL_MDA_DEFINES],
           [[int fd;
             int ret;
             if (mkdir ("conftestdir", 0700) < 0)
diff --git a/m4/fcntl-o.m4 b/m4/fcntl-o.m4
index 747b865759..3ef061d848 100644
--- a/m4/fcntl-o.m4
+++ b/m4/fcntl-o.m4
@@ -1,4 +1,4 @@
-# fcntl-o.m4 serial 6
+# fcntl-o.m4 serial 7
 dnl Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -32,6 +32,7 @@ AC_DEFUN([gl_FCNTL_O_FLAGS],
            # defined sleep(n) _sleep ((n) * 1000)
            #endif
            #include <fcntl.h>
+           ]GL_MDA_DEFINES[
            #ifndef O_NOATIME
             #define O_NOATIME 0
            #endif
diff --git a/m4/fcntl.m4 b/m4/fcntl.m4
index 562ae2395d..ea24f3d64e 100644
--- a/m4/fcntl.m4
+++ b/m4/fcntl.m4
@@ -1,4 +1,4 @@
-# fcntl.m4 serial 9
+# fcntl.m4 serial 10
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -34,6 +34,7 @@ AC_DEFUN([gl_FUNC_FCNTL],
               #include <limits.h>
               #include <sys/resource.h>
               #include <unistd.h>
+              ]GL_MDA_DEFINES[
               #ifndef RLIM_SAVED_CUR
               # define RLIM_SAVED_CUR RLIM_INFINITY
               #endif
diff --git a/m4/fdopen.m4 b/m4/fdopen.m4
index b1909dba0b..f4d4425970 100644
--- a/m4/fdopen.m4
+++ b/m4/fdopen.m4
@@ -1,4 +1,4 @@
-# fdopen.m4 serial 4
+# fdopen.m4 serial 5
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -22,6 +22,7 @@ AC_DEFUN([gl_FUNC_FDOPEN],
           [AC_LANG_SOURCE([[
 #include <stdio.h>
 #include <errno.h>
+]GL_MDA_DEFINES[
 int
 main (void)
 {
diff --git a/m4/fdopendir.m4 b/m4/fdopendir.m4
index d9cc1a0017..454e9adf98 100644
--- a/m4/fdopendir.m4
+++ b/m4/fdopendir.m4
@@ -1,4 +1,4 @@
-# serial 12
+# serial 13
 # See if we need to provide fdopendir.
 
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
@@ -29,6 +29,7 @@ AC_DEFUN([gl_FUNC_FDOPENDIR],
 #include <dirent.h>
 #include <fcntl.h>
 #include <unistd.h>
+]GL_MDA_DEFINES[
 #if !HAVE_DECL_FDOPENDIR
 extern
 # ifdef __cplusplus
diff --git a/m4/fflush.m4 b/m4/fflush.m4
index 620d1a70ed..8f63c254a7 100644
--- a/m4/fflush.m4
+++ b/m4/fflush.m4
@@ -1,4 +1,4 @@
-# fflush.m4 serial 17
+# fflush.m4 serial 18
 
 # Copyright (C) 2007-2020 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -38,7 +38,8 @@ AC_DEFUN([gl_FUNC_FFLUSH_STDIN],
 #else /* on Windows with MSVC */
 # include <io.h>
 #endif
-       ]], [[FILE *f = fopen ("conftest.txt", "r");
+       ]GL_MDA_DEFINES],
+       [[FILE *f = fopen ("conftest.txt", "r");
          char buffer[10];
          int fd;
          int c;
diff --git a/m4/fopen.m4 b/m4/fopen.m4
index 8eab4a699e..a5d687ab9e 100644
--- a/m4/fopen.m4
+++ b/m4/fopen.m4
@@ -1,4 +1,4 @@
-# fopen.m4 serial 11
+# fopen.m4 serial 12
 dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -104,6 +104,7 @@ int main ()
 #include <stdio.h>
 #include <errno.h>
 #include <fcntl.h>
+]GL_MDA_DEFINES[
 int main ()
 {
   FILE *fp = fopen ("conftest.x", "re");
diff --git a/m4/freopen.m4 b/m4/freopen.m4
index c088aadf31..24235aa497 100644
--- a/m4/freopen.m4
+++ b/m4/freopen.m4
@@ -1,4 +1,4 @@
-# freopen.m4 serial 6
+# freopen.m4 serial 7
 dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -19,7 +19,7 @@ AC_DEFUN([gl_FUNC_FREOPEN],
            [AC_LANG_PROGRAM(
               [[#include <stdio.h>
                 #include <unistd.h>
-              ]],
+              ]GL_MDA_DEFINES],
               [[close (0);
                 return !(freopen ("/dev/null", "r", stdin)
                          && getchar () == EOF
diff --git a/m4/futimens.m4 b/m4/futimens.m4
index dc5cfa9411..145b8ff0d5 100644
--- a/m4/futimens.m4
+++ b/m4/futimens.m4
@@ -1,4 +1,4 @@
-# serial 8
+# serial 9
 # See if we need to provide futimens replacement.
 
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
@@ -24,7 +24,8 @@ AC_DEFUN([gl_FUNC_FUTIMENS],
 #include <sys/stat.h>
 #include <unistd.h>
 #include <errno.h>
-]], [[struct timespec ts[2];
+]GL_MDA_DEFINES],
+     [[struct timespec ts[2];
       int fd = creat ("conftest.file", 0600);
       struct stat st;
       if (fd < 0) return 1;
diff --git a/m4/getcwd-abort-bug.m4 b/m4/getcwd-abort-bug.m4
index d89dddf365..d50648d1cb 100644
--- a/m4/getcwd-abort-bug.m4
+++ b/m4/getcwd-abort-bug.m4
@@ -1,4 +1,4 @@
-# serial 12
+# serial 13
 # Determine whether getcwd aborts when the length of the working directory
 # name is unusually large.  Any length between 4k and 16k trigger the bug
 # when using glibc-2.4.90-9 or older.
@@ -45,6 +45,7 @@ AC_DEFUN([gl_FUNC_GETCWD_ABORT_BUG],
 #include <sys/stat.h>
 
 ]gl_PATHMAX_SNIPPET[
+]GL_MDA_DEFINES[
 
 #ifndef S_IRWXU
 # define S_IRWXU 0700
diff --git a/m4/getcwd-path-max.m4 b/m4/getcwd-path-max.m4
index b0eea695c5..859c7de820 100644
--- a/m4/getcwd-path-max.m4
+++ b/m4/getcwd-path-max.m4
@@ -1,4 +1,4 @@
-# serial 24
+# serial 25
 # Check for several getcwd bugs with long file names.
 # If so, arrange to compile the wrapper function.
 
@@ -55,6 +55,8 @@ AC_DEFUN([gl_FUNC_GETCWD_PATH_MAX],
 /* Use the getcwd function, not any macro.  */
 #undef getcwd
 
+]GL_MDA_DEFINES[
+
 #ifndef S_IRWXU
 # define S_IRWXU 0700
 #endif
diff --git a/m4/getcwd.m4 b/m4/getcwd.m4
index ba68c5fb0a..a646b90a32 100644
--- a/m4/getcwd.m4
+++ b/m4/getcwd.m4
@@ -6,7 +6,7 @@
 # with or without modifications, as long as this notice is preserved.
 
 # Written by Paul Eggert.
-# serial 18
+# serial 19
 
 AC_DEFUN([gl_FUNC_GETCWD_NULL],
   [
@@ -21,12 +21,13 @@ AC_DEFUN([gl_FUNC_GETCWD_NULL],
 #        else /* on Windows with MSVC */
 #         include <direct.h>
 #        endif
+         ]GL_MDA_DEFINES[
 #        ifndef getcwd
          char *getcwd ();
 #        endif
 ]], [[
 #if defined _WIN32 && ! defined __CYGWIN__
-/* mingw cwd does not start with '/', but getcwd does allocate.
+/* mingw cwd does not start with '/', but _getcwd does allocate.
    However, mingw fails to honor non-zero size.  */
 #else
            if (chdir ("/") != 0)
@@ -66,7 +67,8 @@ AC_DEFUN([gl_FUNC_GETCWD_SIGNATURE],
     [gl_cv_func_getcwd_posix_signature],
     [AC_COMPILE_IFELSE(
       [AC_LANG_PROGRAM(
-         [[#include <unistd.h>]],
+         [[#include <unistd.h>
+         ]GL_MDA_DEFINES],
          [[extern
            #ifdef __cplusplus
            "C"
diff --git a/m4/getdtablesize.m4 b/m4/getdtablesize.m4
index ab2e3feb37..af328644ad 100644
--- a/m4/getdtablesize.m4
+++ b/m4/getdtablesize.m4
@@ -1,4 +1,4 @@
-# getdtablesize.m4 serial 7
+# getdtablesize.m4 serial 8
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -29,13 +29,16 @@ AC_DEFUN([gl_FUNC_GETDTABLESIZE],
            dnl correctly require setrlimit before getdtablesize() can report
            dnl a larger value.
            AC_RUN_IFELSE([
-             AC_LANG_PROGRAM([[#include <unistd.h>]],
-               [int size = getdtablesize();
-                if (dup2 (0, getdtablesize()) != -1)
-                  return 1;
-                if (size != getdtablesize())
-                  return 2;
-               ])],
+             AC_LANG_PROGRAM(
+               [[#include <unistd.h>]
+                GL_MDA_DEFINES
+               ],
+               [[int size = getdtablesize();
+                 if (dup2 (0, getdtablesize()) != -1)
+                   return 1;
+                 if (size != getdtablesize())
+                   return 2;
+               ]])],
              [gl_cv_func_getdtablesize_works=yes],
              [gl_cv_func_getdtablesize_works=no],
              [case "$host_os" in
diff --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4
index 03da2287d4..c7d1e34f6a 100644
--- a/m4/gnulib-common.m4
+++ b/m4/gnulib-common.m4
@@ -1,4 +1,4 @@
-# gnulib-common.m4 serial 55
+# gnulib-common.m4 serial 56
 dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -663,3 +663,73 @@ AC_DEFUN([gl_CACHE_VAL_SILENT],
 # AS_VAR_COPY was added in autoconf 2.63b
 m4_define_default([AS_VAR_COPY],
 [AS_LITERAL_IF([$1[]$2], [$1=$$2], [eval $1=\$$2])])
+
+dnl Expands to some code for use in .c programs that, on native Windows, defines
+dnl the Microsoft deprecated alias function names to the underscore-prefixed
+dnl actual function names. With this macro, these function names are available
+dnl without linking with '-loldnames' and without generating warnings.
+dnl Usage: Use it after all system header files are included.
+dnl          #include <...>
+dnl          #include <...>
+dnl          ]GL_MDA_DEFINES[
+dnl          ...
+AC_DEFUN([GL_MDA_DEFINES],[
+AC_REQUIRE([_GL_MDA_DEFINES])
+[$gl_mda_defines]
+])
+AC_DEFUN([_GL_MDA_DEFINES],
+[gl_mda_defines='
+#if defined _WIN32 && !defined __CYGWIN__
+#define access    _access
+#define chdir     _chdir
+#define chmod     _chmod
+#define close     _close
+#define creat     _creat
+#define dup       _dup
+#define dup2      _dup2
+#define ecvt      _ecvt
+#define execl     _execl
+#define execle    _execle
+#define execlp    _execlp
+#define execv     _execv
+#define execve    _execve
+#define execvp    _execvp
+#define execvpe   _execvpe
+#define fcloseall _fcloseall
+#define fcvt      _fcvt
+#define fdopen    _fdopen
+#define fileno    _fileno
+#define gcvt      _gcvt
+#define getcwd    _getcwd
+#define getpid    _getpid
+#define getw      _getw
+#define isatty    _isatty
+#define j0        _j0
+#define j1        _j1
+#define jn        _jn
+#define lfind     _lfind
+#define lsearch   _lsearch
+#define lseek     _lseek
+#define memccpy   _memccpy
+#define mkdir     _mkdir
+#define mktemp    _mktemp
+#define open      _open
+#define putenv    _putenv
+#define putw      _putw
+#define read      _read
+#define rmdir     _rmdir
+#define strdup    _strdup
+#define swab      _swab
+#define tempnam   _tempnam
+#define tzset     _tzset
+#define umask     _umask
+#define unlink    _unlink
+#define utime     _utime
+#define wcsdup    _wcsdup
+#define write     _write
+#define y0        _y0
+#define y1        _y1
+#define yn        _yn
+#endif
+'
+])
diff --git a/m4/linkat.m4 b/m4/linkat.m4
index 346e88e5f1..de1bf288b3 100644
--- a/m4/linkat.m4
+++ b/m4/linkat.m4
@@ -1,4 +1,4 @@
-# serial 11
+# serial 12
 # See if we need to provide linkat replacement.
 
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
@@ -58,7 +58,7 @@ AC_DEFUN([gl_FUNC_LINKAT],
               #include <fcntl.h>
               #include <errno.h>
               #include <stdio.h>
-            ]],
+            ]GL_MDA_DEFINES],
             [[int result;
               int fd;
               /* Create a regular file.  */
diff --git a/m4/lseek.m4 b/m4/lseek.m4
index 609c19a0fb..472a1cbba0 100644
--- a/m4/lseek.m4
+++ b/m4/lseek.m4
@@ -1,4 +1,4 @@
-# lseek.m4 serial 10
+# lseek.m4 serial 11
 dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -32,7 +32,8 @@ AC_DEFUN([gl_FUNC_LSEEK],
 #else /* on Windows with MSVC */
 # include <io.h>
 #endif
-]], [[
+]GL_MDA_DEFINES],
+[[
   /* Exit with success only if stdin is seekable.  */
   return lseek (0, (off_t)0, SEEK_CUR) < 0;
 ]])],
diff --git a/m4/mkdir.m4 b/m4/mkdir.m4
index 99212d914b..bd9e088591 100644
--- a/m4/mkdir.m4
+++ b/m4/mkdir.m4
@@ -1,4 +1,4 @@
-# serial 16
+# serial 17
 
 # Copyright (C) 2001, 2003-2004, 2006, 2008-2020 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -16,33 +16,34 @@ AC_DEFUN([gl_FUNC_MKDIR],
   AC_CACHE_CHECK([whether mkdir handles trailing slash],
     [gl_cv_func_mkdir_trailing_slash_works],
     [rm -rf conftest.dir
-      AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-#       include <sys/types.h>
-#       include <sys/stat.h>
-]], [return mkdir ("conftest.dir/", 0700);])],
-      [gl_cv_func_mkdir_trailing_slash_works=yes],
-      [gl_cv_func_mkdir_trailing_slash_works=no],
-      [case "$host_os" in
-                          # Guess yes on Linux systems.
-         linux-* | linux) gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
-                          # Guess yes on glibc systems.
-         *-gnu* | gnu*)   gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
-                          # Guess yes on MSVC, no on mingw.
-         mingw*)          AC_EGREP_CPP([Known], [
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #include <sys/types.h>
+          #include <sys/stat.h>
+          ]GL_MDA_DEFINES],
+          [[return mkdir ("conftest.dir/", 0700);]])],
+       [gl_cv_func_mkdir_trailing_slash_works=yes],
+       [gl_cv_func_mkdir_trailing_slash_works=no],
+       [case "$host_os" in
+                           # Guess yes on Linux systems.
+          linux-* | linux) gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
+                           # Guess yes on glibc systems.
+          *-gnu* | gnu*)   gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
+                           # Guess yes on MSVC, no on mingw.
+          mingw*)          AC_EGREP_CPP([Known], [
 #ifdef _MSC_VER
  Known
 #endif
-                            ],
-                            [gl_cv_func_mkdir_trailing_slash_works="guessing yes"],
-                            [gl_cv_func_mkdir_trailing_slash_works="guessing no"])
-                          ;;
-                          # If we don't know, obey --enable-cross-guesses.
-         *)               gl_cv_func_mkdir_trailing_slash_works="$gl_cross_guess_normal" ;;
-       esac
-      ])
-    rm -rf conftest.dir
-    ]
-  )
+                             ],
+                             [gl_cv_func_mkdir_trailing_slash_works="guessing yes"],
+                             [gl_cv_func_mkdir_trailing_slash_works="guessing no"])
+                           ;;
+                           # If we don't know, obey --enable-cross-guesses.
+          *)               gl_cv_func_mkdir_trailing_slash_works="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -rf conftest.dir
+    ])
   case "$gl_cv_func_mkdir_trailing_slash_works" in
     *yes) ;;
     *)
@@ -53,24 +54,26 @@ AC_DEFUN([gl_FUNC_MKDIR],
   AC_CACHE_CHECK([whether mkdir handles trailing dot],
     [gl_cv_func_mkdir_trailing_dot_works],
     [rm -rf conftest.dir
-      AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-#       include <sys/types.h>
-#       include <sys/stat.h>
-]], [return !mkdir ("conftest.dir/./", 0700);])],
-      [gl_cv_func_mkdir_trailing_dot_works=yes],
-      [gl_cv_func_mkdir_trailing_dot_works=no],
-      [case "$host_os" in
-                        # Guess yes on glibc systems.
-         *-gnu* | gnu*) gl_cv_func_mkdir_trailing_dot_works="guessing yes" ;;
-                        # Guess yes on musl systems.
-         *-musl*)       gl_cv_func_mkdir_trailing_dot_works="guessing yes" ;;
-                        # Guess no on native Windows.
-         mingw*)        gl_cv_func_mkdir_trailing_dot_works="guessing no" ;;
-                        # If we don't know, obey --enable-cross-guesses.
-         *)             gl_cv_func_mkdir_trailing_dot_works="$gl_cross_guess_normal" ;;
-       esac
-      ])
-    rm -rf conftest.dir
+     AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM([[
+          #include <sys/types.h>
+          #include <sys/stat.h>
+          ]GL_MDA_DEFINES],
+          [[return !mkdir ("conftest.dir/./", 0700);]])],
+       [gl_cv_func_mkdir_trailing_dot_works=yes],
+       [gl_cv_func_mkdir_trailing_dot_works=no],
+       [case "$host_os" in
+                         # Guess yes on glibc systems.
+          *-gnu* | gnu*) gl_cv_func_mkdir_trailing_dot_works="guessing yes" ;;
+                         # Guess yes on musl systems.
+          *-musl*)       gl_cv_func_mkdir_trailing_dot_works="guessing yes" ;;
+                         # Guess no on native Windows.
+          mingw*)        gl_cv_func_mkdir_trailing_dot_works="guessing no" ;;
+                         # If we don't know, obey --enable-cross-guesses.
+          *)             gl_cv_func_mkdir_trailing_dot_works="$gl_cross_guess_normal" ;;
+        esac
+       ])
+     rm -rf conftest.dir
     ]
   )
   case "$gl_cv_func_mkdir_trailing_dot_works" in
diff --git a/m4/mkstemp.m4 b/m4/mkstemp.m4
index 28b788955a..392f97cff5 100644
--- a/m4/mkstemp.m4
+++ b/m4/mkstemp.m4
@@ -1,4 +1,4 @@
-#serial 27
+#serial 28
 
 # Copyright (C) 2001, 2003-2007, 2009-2020 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -26,7 +26,8 @@ AC_DEFUN([gl_FUNC_MKSTEMP],
         mkdir conftest.mkstemp
         AC_RUN_IFELSE(
           [AC_LANG_PROGRAM(
-            [AC_INCLUDES_DEFAULT],
+            [AC_INCLUDES_DEFAULT
+             GL_MDA_DEFINES],
             [[int result = 0;
               int i;
               off_t large = (off_t) 4294967295u;
diff --git a/m4/mktime.m4 b/m4/mktime.m4
index 917e759dcb..4e7e423fa5 100644
--- a/m4/mktime.m4
+++ b/m4/mktime.m4
@@ -1,4 +1,4 @@
-# serial 34
+# serial 35
 dnl Copyright (C) 2002-2003, 2005-2007, 2009-2020 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
@@ -54,6 +54,8 @@ AC_DEFUN([gl_FUNC_MKTIME_WORKS],
 # include <signal.h>
 #endif
 
+]GL_MDA_DEFINES[
+
 #ifndef TIME_T_IS_SIGNED
 # define TIME_T_IS_SIGNED 0
 #endif
diff --git a/m4/open-slash.m4 b/m4/open-slash.m4
index 1e57c96960..5d84f2b548 100644
--- a/m4/open-slash.m4
+++ b/m4/open-slash.m4
@@ -1,4 +1,4 @@
-# open-slash.m4 serial 1
+# open-slash.m4 serial 2
 dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -25,6 +25,7 @@ AC_DEFUN([gl_OPEN_TRAILING_SLASH_BUG],
 #if HAVE_UNISTD_H
 # include <unistd.h>
 #endif
+]GL_MDA_DEFINES[
 int main ()
 {
   int result = 0;
diff --git a/m4/poll.m4 b/m4/poll.m4
index b47f2c3050..1a720d6385 100644
--- a/m4/poll.m4
+++ b/m4/poll.m4
@@ -1,4 +1,4 @@
-# poll.m4 serial 19
+# poll.m4 serial 20
 dnl Copyright (c) 2003, 2005-2007, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -19,6 +19,7 @@ AC_DEFUN([gl_FUNC_POLL],
        AC_RUN_IFELSE([AC_LANG_SOURCE([[
 #include <fcntl.h>
 #include <poll.h>
+]GL_MDA_DEFINES[
          int main()
          {
            int result = 0;
diff --git a/m4/posix_spawn.m4 b/m4/posix_spawn.m4
index e97be557de..625b2ad0e8 100644
--- a/m4/posix_spawn.m4
+++ b/m4/posix_spawn.m4
@@ -1,4 +1,4 @@
-# posix_spawn.m4 serial 17
+# posix_spawn.m4 serial 18
 dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -123,6 +123,7 @@ AC_DEFUN([gl_POSIX_SPAWN_WORKS],
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+]GL_MDA_DEFINES[
 
 extern char **environ;
 
@@ -266,6 +267,7 @@ main ()
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+]GL_MDA_DEFINES[
 
 extern char **environ;
 
diff --git a/m4/pread.m4 b/m4/pread.m4
index 6b31fbaca7..9e43dd6a4e 100644
--- a/m4/pread.m4
+++ b/m4/pread.m4
@@ -1,4 +1,4 @@
-# pread.m4 serial 5
+# pread.m4 serial 6
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -37,7 +37,7 @@ changequote([,])dnl
 #include <unistd.h>
 #include <fcntl.h>
 #include <stdio.h>
-             ]],
+             ]GL_MDA_DEFINES],
              [[
 {
   int result = 0;
diff --git a/m4/pselect.m4 b/m4/pselect.m4
index f3e5afe0b3..08a5823c6f 100644
--- a/m4/pselect.m4
+++ b/m4/pselect.m4
@@ -1,4 +1,4 @@
-# pselect.m4 serial 8
+# pselect.m4 serial 9
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -37,7 +37,8 @@ AC_DEFUN([gl_FUNC_PSELECT],
 #endif
 #include <unistd.h>
 #include <errno.h>
-]],[[
+]GL_MDA_DEFINES],
+[[
   fd_set set;
   dup2(0, 16);
   FD_ZERO(&set);
diff --git a/m4/pthread_sigmask.m4 b/m4/pthread_sigmask.m4
index d67511f73d..030862de01 100644
--- a/m4/pthread_sigmask.m4
+++ b/m4/pthread_sigmask.m4
@@ -1,4 +1,4 @@
-# pthread_sigmask.m4 serial 18
+# pthread_sigmask.m4 serial 19
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -220,6 +220,7 @@ int main ()
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+]GL_MDA_DEFINES[
 static volatile int sigint_occurred;
 static void
 sigint_handler (int sig)
diff --git a/m4/ptsname_r.m4 b/m4/ptsname_r.m4
index 181bfa1adb..b77fd73c76 100644
--- a/m4/ptsname_r.m4
+++ b/m4/ptsname_r.m4
@@ -1,4 +1,4 @@
-# ptsname_r.m4 serial 6
+# ptsname_r.m4 serial 7
 dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -90,7 +90,7 @@ AC_DEFUN([gl_PREREQ_PTSNAME_R], [
             #else
             # include <unistd.h>
             #endif
-          ]],
+          ]GL_MDA_DEFINES],
           [[errno = 0;
             isatty (-1);
             return errno == 0;
diff --git a/m4/putenv.m4 b/m4/putenv.m4
index e38f8c5694..3799fb5f13 100644
--- a/m4/putenv.m4
+++ b/m4/putenv.m4
@@ -1,4 +1,4 @@
-# putenv.m4 serial 24
+# putenv.m4 serial 25
 dnl Copyright (C) 2002-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,37 +14,41 @@ AC_DEFUN([gl_FUNC_PUTENV],
   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
   AC_CACHE_CHECK([for putenv compatible with GNU and SVID],
-   [gl_cv_func_svid_putenv],
-   [AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],[[
-    /* Put it in env.  */
-    if (putenv ("CONFTEST_putenv=val"))
-      return 1;
+    [gl_cv_func_svid_putenv],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [AC_INCLUDES_DEFAULT
+           GL_MDA_DEFINES],
+          [[
+            /* Put it in env.  */
+            if (putenv ("CONFTEST_putenv=val"))
+              return 1;
 
-    /* Try to remove it.  */
-    if (putenv ("CONFTEST_putenv"))
-      return 2;
+            /* Try to remove it.  */
+            if (putenv ("CONFTEST_putenv"))
+              return 2;
 
-    /* Make sure it was deleted.  */
-    if (getenv ("CONFTEST_putenv") != 0)
-      return 3;
+            /* Make sure it was deleted.  */
+            if (getenv ("CONFTEST_putenv") != 0)
+              return 3;
 
-    return 0;
-              ]])],
-             gl_cv_func_svid_putenv=yes,
-             gl_cv_func_svid_putenv=no,
-             dnl When crosscompiling, assume putenv is broken.
-             [case "$host_os" in
-                               # Guess yes on glibc systems.
-                *-gnu* | gnu*) gl_cv_func_svid_putenv="guessing yes" ;;
-                               # Guess yes on musl systems.
-                *-musl*)       gl_cv_func_svid_putenv="guessing yes" ;;
-                               # Guess no on native Windows.
-                mingw*)        gl_cv_func_svid_putenv="guessing no" ;;
-                               # If we don't know, obey --enable-cross-guesses.
-                *)             gl_cv_func_svid_putenv="$gl_cross_guess_normal" ;;
-              esac
-             ])
-   ])
+            return 0;
+          ]])],
+       [gl_cv_func_svid_putenv=yes],
+       [gl_cv_func_svid_putenv=no],
+       [dnl When crosscompiling, assume putenv is broken.
+        case "$host_os" in
+                         # Guess yes on glibc systems.
+          *-gnu* | gnu*) gl_cv_func_svid_putenv="guessing yes" ;;
+                         # Guess yes on musl systems.
+          *-musl*)       gl_cv_func_svid_putenv="guessing yes" ;;
+                         # Guess no on native Windows.
+          mingw*)        gl_cv_func_svid_putenv="guessing no" ;;
+                         # If we don't know, obey --enable-cross-guesses.
+          *)             gl_cv_func_svid_putenv="$gl_cross_guess_normal" ;;
+        esac
+       ])
+    ])
   case "$gl_cv_func_svid_putenv" in
     *yes) ;;
     *)
diff --git a/m4/pwrite.m4 b/m4/pwrite.m4
index f8b5dbc249..4c75676ff7 100644
--- a/m4/pwrite.m4
+++ b/m4/pwrite.m4
@@ -1,4 +1,4 @@
-# pwrite.m4 serial 5
+# pwrite.m4 serial 6
 dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -37,7 +37,7 @@ changequote([,])dnl
 #include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
-             ]],
+             ]GL_MDA_DEFINES],
              [[
 {
   /* This test fails on HP-UX 11.00..11.11.  */
diff --git a/m4/rename.m4 b/m4/rename.m4
index a1bd705728..4c19f6125d 100644
--- a/m4/rename.m4
+++ b/m4/rename.m4
@@ -1,4 +1,4 @@
-# serial 32
+# serial 33
 
 # Copyright (C) 2001, 2003, 2005-2006, 2009-2020 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -150,7 +150,7 @@ AC_DEFUN([gl_FUNC_RENAME],
 #               include <stdio.h>
 #               include <stdlib.h>
 #               include <unistd.h>
-                ]],
+                ]GL_MDA_DEFINES],
                 [[int result = 0;
                   if (rename ("conftest.f", "conftest.f1"))
                     result |= 1;
diff --git a/m4/rmdir-errno.m4 b/m4/rmdir-errno.m4
index d03206221d..6eb4f10098 100644
--- a/m4/rmdir-errno.m4
+++ b/m4/rmdir-errno.m4
@@ -1,4 +1,4 @@
-# serial 13
+# serial 14
 
 # Copyright (C) 2000-2001, 2005-2006, 2009-2020 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -26,6 +26,7 @@ AC_DEFUN([gl_FUNC_RMDIR_NOTEMPTY],
 #ifdef HAVE_UNISTD_H
 # include <unistd.h>
 #endif
+]GL_MDA_DEFINES[
         int main ()
         {
           FILE *s;
diff --git a/m4/rmdir.m4 b/m4/rmdir.m4
index ad1b192098..06aaf31e5e 100644
--- a/m4/rmdir.m4
+++ b/m4/rmdir.m4
@@ -1,4 +1,4 @@
-# rmdir.m4 serial 17
+# rmdir.m4 serial 18
 dnl Copyright (C) 2002, 2005, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -22,15 +22,16 @@ AC_DEFUN([gl_FUNC_RMDIR],
            #else /* on Windows with MSVC */
            # include <direct.h>
            #endif
-]], [[int result = 0;
-      if (!rmdir ("conftest.file/"))
-        result |= 1;
-      else if (errno != ENOTDIR)
-        result |= 2;
-      if (!rmdir ("conftest.dir/./"))
-        result |= 4;
-      return result;
-    ]])],
+         ]GL_MDA_DEFINES],
+         [[int result = 0;
+           if (!rmdir ("conftest.file/"))
+             result |= 1;
+           else if (errno != ENOTDIR)
+             result |= 2;
+           if (!rmdir ("conftest.dir/./"))
+             result |= 4;
+           return result;
+         ]])],
        [gl_cv_func_rmdir_works=yes], [gl_cv_func_rmdir_works=no],
        [case "$host_os" in
                            # Guess yes on Linux systems.
diff --git a/m4/select.m4 b/m4/select.m4
index d950460bda..90d2bb9492 100644
--- a/m4/select.m4
+++ b/m4/select.m4
@@ -1,4 +1,4 @@
-# select.m4 serial 11
+# select.m4 serial 12
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -60,7 +60,8 @@ changequote([,])dnl
 #endif
 #include <unistd.h>
 #include <errno.h>
-]],[[
+]GL_MDA_DEFINES],
+[[
   fd_set set;
   dup2(0, 16);
   FD_ZERO(&set);
diff --git a/m4/setenv.m4 b/m4/setenv.m4
index ef03673dce..5dbf913066 100644
--- a/m4/setenv.m4
+++ b/m4/setenv.m4
@@ -1,4 +1,4 @@
-# setenv.m4 serial 29
+# setenv.m4 serial 30
 dnl Copyright (C) 2001-2004, 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -106,35 +106,39 @@ int unsetenv (const char *name);
     dnl OpenBSD 4.7 unsetenv("") does not fail.
     AC_CACHE_CHECK([whether unsetenv obeys POSIX],
       [gl_cv_func_unsetenv_works],
-      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-       #include <stdlib.h>
-       #include <errno.h>
-       extern char **environ;
-      ]], [[
-       char entry1[] = "a=1";
-       char entry2[] = "b=2";
-       char *env[] = { entry1, entry2, NULL };
-       if (putenv ((char *) "a=1")) return 1;
-       if (putenv (entry2)) return 2;
-       entry2[0] = 'a';
-       unsetenv ("a");
-       if (getenv ("a")) return 3;
-       if (!unsetenv ("") || errno != EINVAL) return 4;
-       entry2[0] = 'b';
-       environ = env;
-       if (!getenv ("a")) return 5;
-       entry2[0] = 'a';
-       unsetenv ("a");
-       if (getenv ("a")) return 6;
-      ]])],
-      [gl_cv_func_unsetenv_works=yes], [gl_cv_func_unsetenv_works=no],
-      [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_unsetenv_works="guessing yes" ;;
-                 # If we don't know, obey --enable-cross-guesses.
-         *)      gl_cv_func_unsetenv_works="$gl_cross_guess_normal" ;;
-       esac
-      ])])
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[
+            #include <stdlib.h>
+            #include <errno.h>
+            extern char **environ;
+           ]GL_MDA_DEFINES],
+           [[
+            char entry1[] = "a=1";
+            char entry2[] = "b=2";
+            char *env[] = { entry1, entry2, NULL };
+            if (putenv ((char *) "a=1")) return 1;
+            if (putenv (entry2)) return 2;
+            entry2[0] = 'a';
+            unsetenv ("a");
+            if (getenv ("a")) return 3;
+            if (!unsetenv ("") || errno != EINVAL) return 4;
+            entry2[0] = 'b';
+            environ = env;
+            if (!getenv ("a")) return 5;
+            entry2[0] = 'a';
+            unsetenv ("a");
+            if (getenv ("a")) return 6;
+           ]])],
+         [gl_cv_func_unsetenv_works=yes],
+         [gl_cv_func_unsetenv_works=no],
+         [case "$host_os" in
+                    # Guess yes on glibc systems.
+            *-gnu*) gl_cv_func_unsetenv_works="guessing yes" ;;
+                    # If we don't know, obey --enable-cross-guesses.
+            *)      gl_cv_func_unsetenv_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
     case "$gl_cv_func_unsetenv_works" in
       *yes) ;;
       *)
diff --git a/m4/strncat.m4 b/m4/strncat.m4
index b38ade6c9e..16aefa6623 100644
--- a/m4/strncat.m4
+++ b/m4/strncat.m4
@@ -1,4 +1,4 @@
-# strncat.m4 serial 4
+# strncat.m4 serial 5
 dnl Copyright (C) 2002-2004, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -31,7 +31,8 @@ AC_DEFUN_ONCE([gl_FUNC_STRNCAT],
 #  define MAP_FILE 0
 # endif
 #endif
-]], [[
+]GL_MDA_DEFINES],
+[[
   char *fence = NULL;
 #if HAVE_SYS_MMAN_H && HAVE_MPROTECT
 # if HAVE_MAP_ANONYMOUS
diff --git a/m4/ttyname_r.m4 b/m4/ttyname_r.m4
index 80514d8f1d..869edc87de 100644
--- a/m4/ttyname_r.m4
+++ b/m4/ttyname_r.m4
@@ -1,4 +1,4 @@
-# ttyname_r.m4 serial 10
+# ttyname_r.m4 serial 11
 dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -57,6 +57,7 @@ AC_DEFUN([gl_FUNC_TTYNAME_R],
                [AC_LANG_SOURCE([[
 #include <errno.h>
 #include <unistd.h>
+]GL_MDA_DEFINES[
 int
 main (void)
 {
@@ -96,6 +97,7 @@ changequote([,])dnl
               [AC_LANG_SOURCE([[
 #include <fcntl.h>
 #include <unistd.h>
+]GL_MDA_DEFINES[
 int
 main (void)
 {
diff --git a/m4/unlink-busy.m4 b/m4/unlink-busy.m4
index 7bf6c91a5d..7753f6a1a0 100644
--- a/m4/unlink-busy.m4
+++ b/m4/unlink-busy.m4
@@ -1,4 +1,4 @@
-#serial 14
+#serial 15
 
 dnl From J. David Anglin.
 
@@ -16,7 +16,8 @@ AC_DEFUN([gl_FUNC_UNLINK_BUSY_TEXT],
     [
       AC_RUN_IFELSE(
         [AC_LANG_SOURCE(
-           [AC_INCLUDES_DEFAULT[
+           [AC_INCLUDES_DEFAULT
+            GL_MDA_DEFINES[
             int
             main (int argc, char **argv)
             {
diff --git a/m4/unlink.m4 b/m4/unlink.m4
index b0bb731dc1..69d8ba5cd0 100644
--- a/m4/unlink.m4
+++ b/m4/unlink.m4
@@ -1,4 +1,4 @@
-# unlink.m4 serial 14
+# unlink.m4 serial 15
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -26,7 +26,7 @@ AC_DEFUN([gl_FUNC_UNLINK],
            # include <io.h>
            #endif
            #include <errno.h>
-         ]],
+         ]GL_MDA_DEFINES],
          [[int result = 0;
            if (!unlink ("conftest.file/"))
              result |= 1;
@@ -98,6 +98,7 @@ AC_DEFUN([gl_FUNC_UNLINK],
                 # include <direct.h>
                 # include <io.h>
                 #endif
+                ]GL_MDA_DEFINES[
                 int main ()
                 {
                   int result = 0;
diff --git a/m4/utime.m4 b/m4/utime.m4
index 25d6243da2..f0a8235552 100644
--- a/m4/utime.m4
+++ b/m4/utime.m4
@@ -1,4 +1,4 @@
-# utime.m4 serial 1
+# utime.m4 serial 2
 dnl Copyright (C) 2017-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -8,18 +8,22 @@ AC_DEFUN([gl_FUNC_UTIME],
 [
   AC_REQUIRE([gl_UTIME_H_DEFAULTS])
   AC_REQUIRE([AC_CANONICAL_HOST])
-  AC_CHECK_FUNCS_ONCE([utime])
-  if test $ac_cv_func_utime = no; then
-    HAVE_UTIME=0
-  else
-    case "$host_os" in
-      mingw*)
-        dnl On this platform, the original utime() or _utime() produces
-        dnl timestamps that are affected by the time zone.
-        REPLACE_UTIME=1
-        ;;
-    esac
-  fi
+  case "$host_os" in
+    mingw*)
+      dnl On this platform, the original utime() or _utime() produces
+      dnl timestamps that are affected by the time zone.
+      dnl Use the function name 'rpl_utime' always, in order to avoid a
+      dnl possible conflict with the function name 'utime' from oldnames.lib
+      dnl (MSVC) or liboldnames.a (mingw).
+      REPLACE_UTIME=1
+      ;;
+    *)
+      AC_CHECK_FUNCS([utime])
+      if test $ac_cv_func_utime = no; then
+        HAVE_UTIME=0
+      fi
+      ;;
+  esac
 ])
 
 # Prerequisites of lib/utime.c.
diff --git a/m4/utimens.m4 b/m4/utimens.m4
index 65617ac862..3d31085fc6 100644
--- a/m4/utimens.m4
+++ b/m4/utimens.m4
@@ -3,7 +3,7 @@ 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.
 
-dnl serial 10
+dnl serial 11
 
 AC_DEFUN([gl_UTIMENS],
 [
@@ -24,7 +24,8 @@ AC_DEFUN([gl_UTIMENS],
 #include <stddef.h>
 #include <sys/times.h>
 #include <fcntl.h>
-]], [[    int fd = open ("conftest.file", O_RDWR);
+]GL_MDA_DEFINES],
+        [[int fd = open ("conftest.file", O_RDWR);
           if (fd < 0) return 1;
           if (futimesat (fd, NULL, NULL)) return 2;
         ]])],
diff --git a/m4/utimensat.m4 b/m4/utimensat.m4
index 2bc1bfebb5..e9e4f26b1c 100644
--- a/m4/utimensat.m4
+++ b/m4/utimensat.m4
@@ -1,4 +1,4 @@
-# serial 6
+# serial 7
 # See if we need to provide utimensat replacement.
 
 dnl Copyright (C) 2009-2020 Free Software Foundation, Inc.
@@ -23,7 +23,8 @@ AC_DEFUN([gl_FUNC_UTIMENSAT],
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <unistd.h>
-]],         [[int result = 0;
+]GL_MDA_DEFINES],
+            [[int result = 0;
               const char *f = "conftest.file";
               if (close (creat (f, 0600)))
                 return 1;
diff --git a/m4/utimes.m4 b/m4/utimes.m4
index e1056bbba4..877bfd2a73 100644
--- a/m4/utimes.m4
+++ b/m4/utimes.m4
@@ -1,5 +1,5 @@
 # Detect some bugs in glibc's implementation of utimes.
-# serial 7
+# serial 8
 
 dnl Copyright (C) 2003-2005, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
@@ -34,6 +34,7 @@ AC_DEFUN([gl_FUNC_UTIMES],
 #include <stdio.h>
 #include <utime.h>
 #include <errno.h>
+]GL_MDA_DEFINES[
 
 static int
 inorder (time_t a, time_t b, time_t c)
diff --git a/m4/wcsdup.m4 b/m4/wcsdup.m4
index 662f65a527..d0dde1cdef 100644
--- a/m4/wcsdup.m4
+++ b/m4/wcsdup.m4
@@ -1,4 +1,4 @@
-# wcsdup.m4 serial 2
+# wcsdup.m4 serial 3
 dnl Copyright (C) 2011-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,8 +7,26 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_WCSDUP],
 [
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
-  AC_CHECK_FUNCS_ONCE([wcsdup])
-  if test $ac_cv_func_wcsdup = no; then
+  AC_CACHE_CHECK([for wcsdup],
+    [gl_cv_func_wcsdup],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+   <wchar.h>.
+   BSD/OS 4.0.1 has a bug: <stddef.h>, <stdio.h> and <time.h> must be included
+   before <wchar.h>.  */
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+          ]GL_MDA_DEFINES],
+          [[return wcsdup (L"hello") != NULL;]])
+       ],
+       [gl_cv_func_wcsdup=yes],
+       [gl_cv_func_wcsdup=no])
+    ])
+  if test $gl_cv_func_wcsdup = no; then
     HAVE_WCSDUP=0
   fi
 ])