diff --git a/sc2/src/sc2code/libs/file/dirs.c b/sc2/src/sc2code/libs/file/dirs.c
index b2bab5910..d4a8b70dd 100644
--- a/sc2/src/sc2code/libs/file/dirs.c
+++ b/sc2/src/sc2code/libs/file/dirs.c
@@ -29,6 +29,7 @@
 
 #ifdef WIN32
 #	include <direct.h>
+#	include <ctype.h>
 #endif
 
 /* Try to find a suitable value for %APPDATA% if it isn't defined on