Enable C++11. Synch toolchains with Chrome.

src/base/platform/platform-posix.cc

 // Copyright 2012 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.
 
 // Platform-specific code for POSIX goes here. This is not a platform on its
 // own, but contains the parts which are the same across the POSIX platforms
 // Linux, MacOS, FreeBSD, OpenBSD, NetBSD and QNX.
 
 #include <dlfcn.h>
 #include <errno.h>
@@ skipping 497 matching lines @@
   PlatformData() : thread_(kNoThread) {}
   pthread_t thread_;  // Thread handle for pthread.
   // Synchronizes thread creation
   Mutex thread_creation_mutex_;
 };
 
 Thread::Thread(const Options& options)
     : data_(new PlatformData),
       stack_size_(options.stack_size()),
       start_semaphore_(NULL) {
-  if (stack_size_ > 0 && stack_size_ < PTHREAD_STACK_MIN) {
+  if (stack_size_ > 0 && static_cast<size_t>(stack_size_) < PTHREAD_STACK_MIN) {
     stack_size_ = PTHREAD_STACK_MIN;
   }
   set_name(options.name());
 }
 
 
 Thread::~Thread() {
   delete data_;
 }
 
@@ skipping 199 matching lines @@
 
 void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
   pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
   int result = pthread_setspecific(pthread_key, value);
   DCHECK_EQ(0, result);
   USE(result);
 }
 
 
 } }  // namespace v8::base