diff --git a/bsnes/gb/Core/gb.c b/bsnes/gb/Core/gb.c
index 1e940cfe..08d2183c 100644
--- a/bsnes/gb/Core/gb.c
+++ b/bsnes/gb/Core/gb.c
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdbool.h>
 #include <stdlib.h>