Set proper version to have the "locale_t" identifier.

Index: common/message.c
--- common/message.c.orig
+++ common/message.c
@@ -41,7 +41,7 @@
  * Oh god. glibc is nasty. Changes behavior and definitions of POSIX
  * functions to completely different signatures depending on defines
  */
-#define _POSIX_C_SOURCE 200112L
+#define _POSIX_C_SOURCE 200809L
 
 #include "compat.h"
 #define P11_DEBUG_FLAG P11_DEBUG_LIB
