diff --git a/apps/gui/option_select.c b/apps/gui/option_select.c
index 297afef985..47e585cdbd 100644
--- a/apps/gui/option_select.c
+++ b/apps/gui/option_select.c
@@ -18,6 +18,7 @@
  *
  ****************************************************************************/
 #include <stdlib.h>
+#include <string.h>
 #include "config.h"
 #include "option_select.h"
 #include "sprintf.h"