[Mac] Work around potential pthread_mutex_destroy crashes

src/base/platform/condition-variable.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/platform/condition-variable.h"
 
 #include <errno.h>
 #include <time.h>
 
 #include "src/base/platform/time.h"
@@ skipping 18 matching lines @@
   result = pthread_condattr_destroy(&attr);
 #else
   int result = pthread_cond_init(&native_handle_, NULL);
 #endif
   DCHECK_EQ(0, result);
   USE(result);
 }
 
 
 ConditionVariable::~ConditionVariable() {
+#if defined(V8_OS_MACOSX)
+  // This hack is necessary to avoid a fatal pthreads subsystem bug in the
+  // Darwin kernel. http://crbug.com/517681.
+  {
+    Mutex lock;
+    LockGuard<Mutex> l(&lock);
+    struct timespec ts;
+    ts.tv_sec = 0;
+    ts.tv_nsec = 1;
+    pthread_cond_timedwait_relative_np(&native_handle_, &lock.native_handle(),
+                                       &ts);
+  }
+#endif
   int result = pthread_cond_destroy(&native_handle_);
   DCHECK_EQ(0, result);
   USE(result);
 }
 
 
 void ConditionVariable::NotifyOne() {
   int result = pthread_cond_signal(&native_handle_);
   DCHECK_EQ(0, result);
   USE(result);
@@ skipping 259 matching lines @@
   DCHECK(!result || event->notified_);
   native_handle_.Post(event, result);
 
   return result;
 }
 
 #endif  // V8_OS_POSIX
 
 }  // namespace base
 }  // namespace v8