[CLASSES]: Add a 'visited' flag to struct class

So that tools can mark it as being processed already, such as when ctracer
needs to emit forward declarations for types in function parameters or return
types.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

classes.h

@@ -64,7 +64,8 @@ struct class {
 	unsigned int	 refcnt;
 	signed int	 diff;
 	struct class	 *class_to_diff;
-	unsigned char	 declaration:1;
+	uint8_t		 declaration:1;
+	uint8_t		 visited:1;
 };
 
 struct class_member {