static const char *md_config_set_proxy(cmd_parms *cmd, void *arg, const char *value)
{
    md_srv_conf_t *sc = md_config_get(cmd->server);
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);

    if (err) {
        return err;
    }
    md_util_abs_http_uri_check(cmd->pool, value, &err);
    if (err) {
        return err;
    }
    sc->mc->proxy_url = value;
    (void)arg;
    return NULL;
}
static const char *md_config_set_proxy(cmd_parms *cmd, void *arg, const char *value)
{
    md_srv_conf_t *sc = md_config_get(cmd->server);
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);

    if (err) {
        return err;
    }
    md_util_abs_http_uri_check(cmd->pool, value, &err);
    if (err) {
        return err;
    }
    sc->mc->proxy_url = value;
    (void)arg;
    return NULL;
}