simplify singleton registration

stepmania/src/GameState.cpp

@@ -118,10 +118,22 @@ GameState::GameState() :
 	/* Don't reset yet; let the first screen do it, so we can
 	 * use PREFSMAN and THEME. */
 //	Reset();
+
+	// Register with Lua.
+	{
+		Lua *L = LUA->Get();
+		lua_pushstring( L, "GAMESTATE" );
+		this->PushSelf( L );
+		lua_settable( L, LUA_GLOBALSINDEX );
+		LUA->Release( L );
+	}
 }
 
 GameState::~GameState()
 {
+	// Unregister with Lua.
+	LUA->UnsetGlobal( "GAMESTATE" );
+
 	FOREACH_PlayerNumber( p )
 		SAFE_DELETE( m_pPlayerState[p] );
 	FOREACH_MultiPlayer( p )
@@ -2116,16 +2128,6 @@ public:
 		ADD_METHOD( GetCurrentStyle );
 
 		Luna<T>::Register( L );
-
-		// Add global singleton if constructed already.  If it's not constructed yet,
-		// then we'll register it later when we reinit Lua just before 
-		// initializing the display.
-		if( GAMESTATE )
-		{
-			lua_pushstring(L, "GAMESTATE");
-			GAMESTATE->PushSelf( L );
-			lua_settable(L, LUA_GLOBALSINDEX);
-		}
 	}
 };