static GSource *mux_chr_add_watch(CharDriverState *s, GIOCondition cond)
{
    MuxDriver *d = s->opaque;
    CharDriverState *chr = qemu_chr_fe_get_driver(&d->chr);

    return chr->chr_add_watch(chr, cond);
}
static GSource *mux_chr_add_watch(CharDriverState *s, GIOCondition cond)
{
    MuxDriver *d = s->opaque;
    CharDriverState *chr = qemu_chr_fe_get_driver(&d->chr);

    return chr->chr_add_watch(chr, cond);
}