SYNOPSIS
        mixed prepare_destruct(object obj)

DESCRIPTION
        Prepare the destruction of the object obj. Return 0 if the
        object is ready for destruction, any other value will abort
        the attempt. If a string is returned, an error with the string
        as message will be issued.

        The interpreter calls this function whenever an object shall
        be destructed. It expects, that this function cleans the
        inventory of the object, or the destruct will fail.
        Furthermore, the function could notify the former inventory
        objects that their holder is under destruction (useful to move
        users out of rooms which re updated); and it could announce
        systemwide the destruction(quitting) of users.

        Strange things will happen if the mastor object does not
        provide this function.

SEE ALSO
        remove_player(M), destruct(E)
