Fix warning about intro data type in setup files

src/files/setup/setupold.c

@@ -4,7 +4,7 @@
 
 #include "stagesetup.h"
 
-u8 intro[];
+s32 intro[];
 u8 props[];
 struct path paths[];
 struct ailist ailists[];
@@ -30,7 +30,7 @@ u8 props[] = {
 	endprops
 };
 
-u8 intro[] = {
+s32 intro[] = {
 	outfit(OUTFIT_DEFAULT)
 	endintro
 };