Import new gnulib.

m4/mbstate_t.m4

@@ -1,5 +1,5 @@
-# mbstate_t.m4 serial 12
-dnl Copyright (C) 2000-2002, 2008-2010 Free Software Foundation, Inc.
+# mbstate_t.m4 serial 13
+dnl Copyright (C) 2000-2002, 2008-2013 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.
@@ -20,7 +20,14 @@ AC_DEFUN([AC_TYPE_MBSTATE_T],
      [AC_COMPILE_IFELSE(
         [AC_LANG_PROGRAM(
            [AC_INCLUDES_DEFAULT[
-#           include <wchar.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>]],
            [[mbstate_t x; return sizeof x;]])],
         [ac_cv_type_mbstate_t=yes],
         [ac_cv_type_mbstate_t=no])])