ArgParser::argUOpositional(char* arg)
{
    if (o.under_overlay->filename)
    {
        usage(o.under_overlay->which + " file already specified");
    }
    else
    {
        o.under_overlay->filename = arg;
    }
}
ArgParser::argUOpositional(char* arg)
{
    if (o.under_overlay->filename)
    {
        usage(o.under_overlay->which + " file already specified");
    }
    else
    {
        o.under_overlay->filename = arg;
    }
}