set flag to allow forced unload of a running VM

required to prevent a client from exiting if the server disconnects (bug 3585)

code/qcommon/qcommon.h

@@ -325,6 +325,8 @@ vm_t	*VM_Create( const char *module, intptr_t (*systemCalls)(intptr_t *),
 
 void	VM_Free( vm_t *vm );
 void	VM_Clear(void);
+void	VM_Forced_Unload_Start(void);
+void	VM_Forced_Unload_Done(void);
 vm_t	*VM_Restart( vm_t *vm );
 
 intptr_t		QDECL VM_Call( vm_t *vm, int callNum, ... );