Fix Mac warnings

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 865 matching lines @@
 class AllocationSiteUsageContext;
 class DictionaryElementsAccessor;
 class ElementsAccessor;
 class Failure;
 class FixedArrayBase;
 class GlobalObject;
 class ObjectVisitor;
 class StringStream;
 // We cannot just say "class Type;" if it is created from a template... =8-?
 template<class> class TypeImpl;
-class HeapTypeConfig;
+struct HeapTypeConfig;
 typedef TypeImpl<HeapTypeConfig> Type;
 
 
 // A template-ized version of the IsXXX functions.
 template <class C> inline bool Is(Object* obj);
 
 #ifdef VERIFY_HEAP
 #define DECLARE_VERIFIER(Name) void Name##Verify();
 #else
 #define DECLARE_VERIFIER(Name)
@@ skipping 9733 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_