NAME
        RemHead -- remove the head node from a list

   SYNOPSIS
        node = RemHead(list)
        D0             A0

        struct node *remhead(struct list *);

   FUNCTION
        Get a pointer to the head node and remove it from the list.
        Assembly programmers may prefer to use the REMHEAD 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(), remtail()