diff --git a/mkpasswd.c b/mkpasswd.c
index ce0c763..30c2423 100644
--- a/mkpasswd.c
+++ b/mkpasswd.c
@@ -19,6 +19,7 @@
 /* for crypt, snprintf and strcasecmp */
 #define _XOPEN_SOURCE 500
 #define _BSD_SOURCE 1
+#define _DEFAULT_SOURCE 1
 #define __EXTENSIONS__ 1
 
 /* System library */