/* generate list of overplots */
_ovrlist()
{
        local i = 1, s = "", p;

        if (numitems == 1) return(_nonestr);

        for (i = 1; i < numitems; i++)
        {
                p = sprintf("%d", i);
                if (i < numitems - 1) p = strcat(p, strescape("\n"));
                s = strcat(s, p);
        }
        return(s);
}