Forcing "POSIX 1003.1-2001 with XSI" removes locale_t from <locale.h>.
This breaks including libintl.h, since gettext is built with locale_t
in view.

Index: misc/tune2fs.c
--- misc/tune2fs.c.orig
+++ misc/tune2fs.c
@@ -25,7 +25,7 @@
  * 94/03/06	- Added the checks interval from Uwe Ohse (uwe@tirka.gun.de)
  */
 
-#define _XOPEN_SOURCE 600 /* for inclusion of strptime() */
+/* #define _XOPEN_SOURCE 600 */ /* for inclusion of strptime() */
 #include "config.h"
 #include <fcntl.h>
 #include <grp.h>
