diff --git a/src/gdd/aitTypes.h b/src/gdd/aitTypes.h
index 8ba9f2ccf..b8484eb64 100644
--- a/src/gdd/aitTypes.h
+++ b/src/gdd/aitTypes.h
@@ -24,7 +24,7 @@
 
 #include "shareLib.h"
 
-typedef char                aitInt8;
+typedef signed char         aitInt8;
 typedef unsigned char       aitUint8;
 typedef short               aitInt16;
 typedef unsigned short      aitUint16;