1 files changed, 11 insertions, 22 deletions

diff --git a/gl/m4/btowc.m4 b/gl/m4/btowc.m4
index 978a06e9..d2b2fe85 100644
--- a/gl/m4/btowc.m4
+++ b/gl/m4/btowc.m4
@@ -1,5 +1,5 @@
-# btowc.m4 serial 10
-dnl Copyright (C) 2008-2013 Free Software Foundation, Inc.
+# btowc.m4 serial 12
+dnl Copyright (C) 2008-2021 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.
@@ -10,7 +10,7 @@ AC_DEFUN([gl_FUNC_BTOWC],
 
   dnl Check whether <wchar.h> is usable at all, first. Otherwise the test
   dnl program below may lead to an endless loop. See
-  dnl <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>.
+  dnl <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42440>.
   AC_REQUIRE([gl_WCHAR_H_INLINE_OK])
 
   AC_CHECK_FUNCS_ONCE([btowc])
@@ -28,14 +28,6 @@ AC_DEFUN([gl_FUNC_BTOWC],
       [
         AC_RUN_IFELSE(
           [AC_LANG_SOURCE([[
-#include <string.h>
-/* 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>
 int main ()
 {
@@ -50,6 +42,8 @@ changequote(,)dnl
            case "$host_os" in
                       # Guess no on Cygwin.
              cygwin*) gl_cv_func_btowc_nul="guessing no" ;;
+                      # Guess yes on native Windows.
+             mingw*)  gl_cv_func_btowc_nul="guessing yes" ;;
                       # Guess yes otherwise.
              *)       gl_cv_func_btowc_nul="guessing yes" ;;
            esac
@@ -65,24 +59,19 @@ changequote([,])dnl
         dnl is present.
 changequote(,)dnl
         case "$host_os" in
-                 # Guess no on IRIX.
-          irix*) gl_cv_func_btowc_eof="guessing no" ;;
-                 # Guess yes otherwise.
-          *)     gl_cv_func_btowc_eof="guessing yes" ;;
+                  # Guess no on IRIX.
+          irix*)  gl_cv_func_btowc_eof="guessing no" ;;
+                  # Guess yes on native Windows.
+          mingw*) gl_cv_func_btowc_eof="guessing yes" ;;
+                  # Guess yes otherwise.
+          *)      gl_cv_func_btowc_eof="guessing yes" ;;
         esac
 changequote([,])dnl
         if test $LOCALE_FR != none; then
           AC_RUN_IFELSE(
             [AC_LANG_SOURCE([[
 #include <locale.h>
-#include <string.h>
-/* 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>
 int main ()
 {