Forcing POSIX 1003.2-1992 removes locale_t from <locale.h>.
This breaks including libintl.h, since gettext is built with locale_t
in view.

Index: src/mpegvolume.c
--- src/mpegvolume.c.orig
+++ src/mpegvolume.c
@@ -17,7 +17,7 @@
 
 /* interface to the mad decoding library */
 
-#define _POSIX_C_SOURCE 2
+/* #define _POSIX_C_SOURCE 2 */
 
 #include "config.h"
 
