Adding string.h
diff --git a/demos/src/ftgrays.c b/demos/src/ftgrays.c
index 592aae8..899789d 100644
--- a/demos/src/ftgrays.c
+++ b/demos/src/ftgrays.c
@@ -56,6 +56,10 @@
#include <ftimage.h>
+#if 1
+#include <string.h>
+#endif
+
#define ErrRaster_Invalid_Outline -1
#include "ftgrays.h"