diff --git a/sdust.c b/sdust.c
index cba4887..7c8140a 100644
--- a/sdust.c
+++ b/sdust.c
@@ -1,3 +1,4 @@
+#define _POSIX_SOURCE
 #include <string.h>
 #include <stdint.h>
 #include <stdio.h>