Make 'hidden' the default visibility for gcc. Add build option,

include/v8.h

 // Copyright 2007-2008 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 2707 matching lines @@
   static const int kMapInstanceTypeOffset = sizeof(void*) + sizeof(int);
   static const int kStringResourceOffset = 2 * sizeof(void*);
   static const int kProxyProxyOffset = sizeof(void*);
   static const int kJSObjectHeaderSize = 3 * sizeof(void*);
   static const int kFullStringRepresentationMask = 0x07;
   static const int kExternalTwoByteRepresentationTag = 0x03;
   static const int kAlignedPointerShift = 2;
 
   // These constants are compiler dependent so their values must be
   // defined within the implementation.
-  static int kJSObjectType;
-  static int kFirstNonstringType;
-  static int kProxyType;
+  V8EXPORT static int kJSObjectType;
+  V8EXPORT static int kFirstNonstringType;
+  V8EXPORT static int kProxyType;
 
   static inline bool HasHeapObjectTag(internal::Object* value) {
     return ((reinterpret_cast<intptr_t>(value) & kHeapObjectTagMask) ==
             kHeapObjectTag);
   }
   
   static inline bool HasSmiTag(internal::Object* value) {
     return ((reinterpret_cast<intptr_t>(value) & kSmiTagMask) == kSmiTag);
   }
   
@@ skipping 339 matching lines @@
 
 }  // namespace v8
 
 
 #undef V8EXPORT
 #undef V8EXPORT_INLINE
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_