X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fwmemcmp.m4;h=0f1d7ec80d42505711839596890fb374129fc893;hb=da8054d48dc22e1c051db54049e005d51a006e69;hp=ec86e422222ea3cc62e080f680348bf44434c682;hpb=abc17284134fd97bb3f734f2c7e9afa040956118;p=gnulib.git

diff --git a/m4/wmemcmp.m4 b/m4/wmemcmp.m4
index ec86e4222..0f1d7ec80 100644
--- a/m4/wmemcmp.m4
+++ b/m4/wmemcmp.m4
@@ -1,5 +1,5 @@
-# wmemcmp.m4 serial 2
-dnl Copyright (C) 2011 Free Software Foundation, Inc.
+# wmemcmp.m4 serial 3
+dnl Copyright (C) 2011-2013 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.
@@ -7,8 +7,26 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_WMEMCMP],
 [
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
-  AC_CHECK_FUNCS_ONCE([wmemcmp])
-  if test $ac_cv_func_wmemcmp = no; then
+  dnl We cannot use AC_CHECK_FUNCS here, because the MSVC 9 header files
+  dnl provide this function as an inline function definition.
+  AC_CACHE_CHECK([for wmemcmp], [gl_cv_func_wmemcmp],
+    [AC_COMPILE_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>
+]],
+          [[return ! wmemcmp ((const wchar_t *) 0, (const wchar_t *) 0, 0);]])
+       ],
+       [gl_cv_func_wmemcmp=yes],
+       [gl_cv_func_wmemcmp=no])
+    ])
+  if test $gl_cv_func_wmemcmp = no; then
     HAVE_WMEMCMP=0
   fi
 ])