Fix: use std::atomic for m_worldLoopCounter

Closes cmangos#614

Co-Authored-By: Andreas J. Bathe <ajbathe@users.noreply.github.com>

Author: killerwife

src/game/World/World.cpp

@@ -95,7 +95,7 @@ extern void LoadGameObjectModelList();
 
 volatile bool World::m_stopEvent = false;
 uint8 World::m_ExitCode = SHUTDOWN_EXIT_CODE;
-volatile uint32 World::m_worldLoopCounter = 0;
+std::atomic<uint32> World::m_worldLoopCounter = 0;
 
 float World::m_MaxVisibleDistanceOnContinents = DEFAULT_VISIBILITY_DISTANCE;
 float World::m_MaxVisibleDistanceInInstances  = DEFAULT_VISIBILITY_INSTANCE;

src/game/World/World.h

@@ -41,6 +41,7 @@
 #include <utility>
 #include <vector>
 #include <array>
+#include <atomic>
 
 class Object;
 class ObjectGuid;
@@ -392,7 +393,7 @@ struct CliCommandHolder
 class World
 {
     public:
-        static volatile uint32 m_worldLoopCounter;
+        static std::atomic<uint32> m_worldLoopCounter;
 
         World();
         ~World();