diff --git a/config.l b/config.l
index 4f49f85..8555dae 100644
--- a/config.l
+++ b/config.l
@@ -4,6 +4,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <errno.h>
 
 #include "y.tab.h"
 #include "dgamelaunch.h"