- explicitly destroy the AltHUD when exiting.

This is to avoid problems with the GC on shutdown.

source/core/gamecontrol.cpp

@@ -165,6 +165,7 @@ bool G_Responder(event_t* ev);
 void HudScaleChanged();
 bool M_SetSpecialMenu(FName& menu, int param);
 void OnMenuOpen(bool makeSound);
+void DestroyAltHUD();
 
 DStatusBarCore* StatusBar;
 
@@ -622,6 +623,7 @@ int GameMain()
 	}
 	//DeleteScreenJob();
 	if (gi) gi->FreeLevelData();
+	DestroyAltHUD();
 	DeinitMenus();
 	if (StatusBar) StatusBar->Destroy();
 	StatusBar = nullptr;

source/core/shared_hud.cpp

@@ -134,14 +134,18 @@ static DObject* DoCreateAltHUD(const FName classname)
 	return althud;
 }
 
-void CreateAltHUD()
+void DestroyAltHUD()
 {
 	if (AltHud)
 	{
 		AltHud->Destroy();
 		AltHud = nullptr;
 	}
+}
 
+void CreateAltHUD()
+{
+	DestroyAltHUD();
 	/*
 	if (!hud_althud_forceinternal)
 		AltHud = DoCreateAltHUD(gameinfo.althudclass);