Use C++11 mutexes only (remove compat code) (#5922)

* Fix event LINT & remove default constructor/destructors
* remove compat code & modernize autolock header

src/threading/mutex_auto_lock.h

@@ -23,40 +23,8 @@ FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 DEALINGS IN THE SOFTWARE.
 */
 
-#ifndef THREADING_MUTEX_AUTO_LOCK_H
-#define THREADING_MUTEX_AUTO_LOCK_H
-
-#include "threads.h"
-
-#if USE_CPP11_MUTEX
-	#include <mutex>
-	using MutexAutoLock = std::unique_lock<std::mutex>;
-	using RecursiveMutexAutoLock = std::unique_lock<std::recursive_mutex>;
-#else
-
-#include "threading/mutex.h"
-
-
-class MutexAutoLock
-{
-public:
-	MutexAutoLock(Mutex &m) : mutex(m) { mutex.lock(); }
-	~MutexAutoLock() { mutex.unlock(); }
-
-private:
-	Mutex &mutex;
-};
-
-class RecursiveMutexAutoLock
-{
-public:
-	RecursiveMutexAutoLock(RecursiveMutex &m) : mutex(m) { mutex.lock(); }
-	~RecursiveMutexAutoLock() { mutex.unlock(); }
-
-private:
-	RecursiveMutex &mutex;
-};
-#endif
-
-#endif
+#pragma once
 
+#include <mutex>
+using MutexAutoLock = std::unique_lock<std::mutex>;
+using RecursiveMutexAutoLock = std::unique_lock<std::recursive_mutex>;