use protocol_isEqual to compare Protocols, rather than isEqual:

It appears that -[Protocol isEqual:] is broken, at least on i386,
and doesn't recognize two equal protocols that aren't the same
pointer. The function works. Don't ask me why the method doesn't
just call through to the function....

RTProtocol.m

@@ -71,7 +71,7 @@ - (NSString *)description
 - (BOOL)isEqual: (id)other
 {
     return [other isKindOfClass: [RTProtocol class]] &&
-           [[self objCProtocol] isEqual: [other objCProtocol]];
+           protocol_isEqual([self objCProtocol], [other objCProtocol]);
 }
 
 - (NSUInteger)hash