A small cleanup of MacOSMutex constructor

src/platform-macos.cc

 // 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 393 matching lines @@
 
 void Thread::YieldCPU() {
   sched_yield();
 }
 
 
 class MacOSMutex : public Mutex {
  public:
 
   MacOSMutex() {
-    // For some reason the compiler doesn't allow you to write
-    // "this->mutex_ = PTHREAD_..." directly on mac.
-    pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
     pthread_mutexattr_t attr;
     pthread_mutexattr_init(&attr);
     pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
-    pthread_mutex_init(&m, &attr);
-    mutex_ = m;
+    pthread_mutex_init(&mutex_, &attr);
   }
 
   ~MacOSMutex() { pthread_mutex_destroy(&mutex_); }
 
   int Lock() { return pthread_mutex_lock(&mutex_); }
 
   int Unlock() { return pthread_mutex_unlock(&mutex_); }
 
  private:
   pthread_mutex_t mutex_;
@@ skipping 173 matching lines @@
 
   // Deallocate Mach port for thread.
   if (IsProfiling()) {
     mach_port_deallocate(data_->task_self_, data_->profiled_thread_);
   }
 }
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal