PIMutex typedef std::mutex, patch PIMutexLocker, replace volatile by atomic

lib/main/thread/pithread.h

@@ -246,7 +246,7 @@ protected:
 	//! Function executed once at the end of thread.
 	virtual void end() {;}
 
-	volatile bool terminating, running_, lockRun;
+	std::atomic_bool terminating, running_, lockRun;
 	int delay_, policy_;
 	llong tid_;
 	void * data_;