From 7b3b0a81fa1ad7d1390156a0ed5dd6b7017b520e Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Tue, 4 Oct 2011 01:27:54 +0200
Subject: [PATCH] wmemchr: Support for MSVC.

* m4/wmemchr.m4 (gl_FUNC_WMEMCHR): Use a small test program to test
whether wmemchr() exists.
---
 ChangeLog     |  6 ++++++
 m4/wmemchr.m4 | 24 +++++++++++++++++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7bacbfe8a..f1d7592f8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2011-10-03  Bruno Haible  <bruno@clisp.org>
 
+	wmemchr: Support for MSVC.
+	* m4/wmemchr.m4 (gl_FUNC_WMEMCHR): Use a small test program to test
+	whether wmemchr() exists.
+
+2011-10-03  Bruno Haible  <bruno@clisp.org>
+
 	glthread/*, strsignal: Support for MSVC.
 	* lib/glthread/cond.h: Define WIN32_LEAN_AND_MEAN, so as to avoid
 	including <winsock.h> on MSVC 9.
diff --git a/m4/wmemchr.m4 b/m4/wmemchr.m4
index 285304530..082bb8703 100644
--- a/m4/wmemchr.m4
+++ b/m4/wmemchr.m4
@@ -1,4 +1,4 @@
-# wmemchr.m4 serial 2
+# wmemchr.m4 serial 3
 dnl Copyright (C) 2011 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_WMEMCHR],
 [
   AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
-  AC_CHECK_FUNCS_ONCE([wmemchr])
-  if test $ac_cv_func_wmemchr = 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 wmemchr], [gl_cv_func_wmemchr],
+    [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 ! wmemchr ((const wchar_t *) 0, (wchar_t) ' ', 0);]])
+       ],
+       [gl_cv_func_wmemchr=yes],
+       [gl_cv_func_wmemchr=no])
+    ])
+  if test $gl_cv_func_wmemchr = no; then
     HAVE_WMEMCHR=0
   fi
 ])
-- 
2.11.0