diff -up src/chewingutil.c.asprintf src/chewingutil.c
--- src/chewingutil.c.asprintf	2013-02-03 10:45:45.202307401 +1000
+++ src/chewingutil.c	2013-02-03 10:46:49.105306792 +1000
@@ -17,6 +17,7 @@
 #include <config.h>
 #endif
 
+#define _GNU_SOURCE
 #include <ctype.h>
 #include <string.h>
 #include <stdio.h>