NAME
        RemTail -- remove the tail node from a list

   SYNOPSIS
        node = RemTail(list)
        D0             A0

        struct node *remtail(struct list *);

   FUNCTION
        remove the last node from a list, and return a pointer to it. if
        the list is empty, return zero. Assembly programmers may prefer to
        use the REMTAIL macro from "exec/lists.i".

   WARNING
        This function does not arbitrate for access to the list.  The
        calling task must be the owner of the involved list.

   INPUTS
        list - a pointer to the target list header

   RESULT
        node - the node removed or zero when empty list

   SEE ALSO
        addhead(), addtail(), enqueue(), insert(), remove(), remhead()