Core/Game: Move singleton instances into compilation units

* Fixes issues when building shared libraries
  (prevents gcc and clang from providing several instance)

(cherry picked from commit 329225b40d110bed634f8cd0a1ab5c6dc7bbbdd1)

1 files changed, 1 insertions, 5 deletions

diff --git a/src/server/game/Scripting/ScriptSystem.h b/src/server/game/Scripting/ScriptSystem.h
index 74c51e5b136..9e6a0d2a5a7 100644
--- a/src/server/game/Scripting/ScriptSystem.h
+++ b/src/server/game/Scripting/ScriptSystem.h
@@ -52,11 +52,7 @@ class SystemMgr
         ~SystemMgr() { }
 
     public:
-        static SystemMgr* instance()
-        {
-            static SystemMgr instance;
-            return &instance;
-        }
+        static SystemMgr* instance();
 
         typedef std::unordered_map<uint32, ScriptPointVector> PointMoveMap;