diff --git a/engine/client/application/Miff/src/linux/parser.yac b/engine/client/application/Miff/src/linux/parser.yac
index 8412cbea..b40006e4 100644
--- a/engine/client/application/Miff/src/linux/parser.yac
+++ b/engine/client/application/Miff/src/linux/parser.yac
@@ -27,7 +27,7 @@
 #include <string.h>
 #include <stdlib.h>			/* for toupper() */
 #include <wchar.h>			/* for wide character (16bit) strings */
-
+#include <ctype.h> 			/* for strtoupper and strtolower */
 #include <stdio.h>
 
 /*----------------------------------------------------------------**