Qt4: Add menucolors

The Qt4 windowport already supported my 3.4.3 menucolors patch, so
adding that was simple.

src/options.c

@@ -1747,7 +1747,7 @@ char *tmpstr;
 
 boolean
 get_menu_coloring(str, color, attr)
-char *str;
+const char *str;
 int *color, *attr;
 {
     struct menucoloring *tmpmc;