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: e2fsck/unix.c
--- e2fsck/unix.c.orig
+++ e2fsck/unix.c
@@ -9,7 +9,7 @@
  * %End-Header%
  */
 
-#define _XOPEN_SOURCE 600 /* for inclusion of sa_handler in Solaris */
+/* #define _XOPEN_SOURCE 600 */ /* for inclusion of sa_handler in Solaris */
 
 #include "config.h"
 #include <stdio.h>
