Fix the Mac OS debug build

src/platform.h

 // Copyright 2006-2008 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 403 matching lines @@
   static void SetThreadLocalInt(LocalStorageKey key, int value) {
     SetThreadLocal(key, reinterpret_cast<void*>(static_cast<intptr_t>(value)));
   }
   static bool HasThreadLocal(LocalStorageKey key) {
     return GetThreadLocal(key) != NULL;
   }
 
   // A hint to the scheduler to let another thread run.
   static void YieldCPU();
 
+  // The thread name length is limited to 16 based on Linux's implementation of
+  // prctl().
+  static const int kMaxThreadNameLength = 16;
  private:
   void set_name(const char *name);
 
   class PlatformData;
   PlatformData* data_;
 
-  // The thread name length is limited to 16 based on Linux's implementation of
-  // prctl().
-  static const int kMaxThreadNameLength = 16;
   char name_[kMaxThreadNameLength];
 
   DISALLOW_COPY_AND_ASSIGN(Thread);
 };
 
 
 // ----------------------------------------------------------------------------
 // Mutex
 //
 // Mutexes are used for serializing access to non-reentrant sections of code.
@@ skipping 181 matching lines @@
   PlatformData* data_;  // Platform specific data.
   int samples_taken_;  // Counts stack samples taken.
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_