diff --git a/tools/utilbox.c b/tools/utilbox.c
index 24a1ea5..0964069 100644
--- a/tools/utilbox.c
+++ b/tools/utilbox.c
@@ -16,6 +16,7 @@
 
 
 #include <unistd.h>
+#include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <libgen.h>