--- a/m4/mbstate_t.m4
+++ b/m4/mbstate_t.m4
@@ -1,4 +1,10 @@
-# serial 9
+# mbstate_t.m4 serial 9
+dnl Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
+dnl This file is free software, distributed under the terms of the GNU
+dnl General Public License.  As a special exception to the GNU General
+dnl Public License, this file may be distributed as part of a program
+dnl that contains a configuration script generated by Autoconf, under
+dnl the same distribution terms as the rest of that program.
 
 # From Paul Eggert.
 
@@ -6,24 +12,21 @@
 # so you can't declare an object of that type.
 # Check for this incompatibility with Standard C.
 
-# Include stdlib.h first, because otherwise this test would fail on Linux
-# (at least glibc-2.1.3) because the "_XOPEN_SOURCE 500" definition elicits
-# a syntax error in wchar.h due to the use of undefined __int32_t.
-
-AC_DEFUN([AC_MBSTATE_T],
-  [
-   AC_CHECK_HEADERS(stdlib.h)
-
-   AC_CACHE_CHECK([for mbstate_t], ac_cv_type_mbstate_t,
-    [AC_TRY_COMPILE([
-#if HAVE_STDLIB_H
-# include <stdlib.h>
-#endif
-#include <wchar.h>],
-      [mbstate_t x; return sizeof x;],
-      ac_cv_type_mbstate_t=yes,
-      ac_cv_type_mbstate_t=no)])
-   if test $ac_cv_type_mbstate_t = no; then
-     AC_DEFINE(mbstate_t, int,
+# AC_TYPE_MBSTATE_T
+# -----------------
+AC_DEFUN([AC_TYPE_MBSTATE_T],
+  [AC_CACHE_CHECK([for mbstate_t], ac_cv_type_mbstate_t,
+     [AC_COMPILE_IFELSE(
+	[AC_LANG_PROGRAM(
+	   [AC_INCLUDES_DEFAULT
+#	    include <wchar.h>],
+	   [mbstate_t x; return sizeof x;])],
+	[ac_cv_type_mbstate_t=yes],
+	[ac_cv_type_mbstate_t=no])])
+   if test $ac_cv_type_mbstate_t = yes; then
+     AC_DEFINE([HAVE_MBSTATE_T], 1,
+	       [Define to 1 if <wchar.h> declares mbstate_t.])
+   else
+     AC_DEFINE([mbstate_t], int,
 	       [Define to a type if <wchar.h> does not define.])
    fi])