fixed missing header file

diff --git a/tests/test_io_dir_list.c b/tests/test_io_dir_list.c
index 6413eb9..6fbb3fb 100644 (file)
--- a/tests/test_io_dir_list.c
+++ b/tests/test_io_dir_list.c
@@ -19,6 +19,7 @@
 
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "../src/lib/pio.h"