diff --git a/demo.c b/demo.c
index 11d85f2..1b148b5 100644
--- a/demo.c
+++ b/demo.c
@@ -1,5 +1,8 @@
+// we want optarg
+#define _XOPEN_SOURCE 600
+
 #include <stdio.h>
-#include <getopt.h>
+#include <unistd.h>
 #include <errno.h>
 
 #include "termkey.h"