Landing patch for Timur Iskhodzhanov.

Reviewed at http://codereview.chromium.org/160099

The original MacOSMutex constructor makes data race detectors a little
bit crazy. Also, the new version is simpler and easier to understand.



git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2535 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-macos.cc

@@ -424,14 +424,10 @@ 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_); }