curl_easy_setopt(curl, CURLOPT_PORT, server.port);
 
        if (server.auth_method) {
+#if LIBCURL_VERSION_NUM < 0x072200
+               warning("No LOGIN_OPTIONS support in this cURL version");
+#else
                struct strbuf auth = STRBUF_INIT;
                strbuf_addstr(&auth, "AUTH=");
                strbuf_addstr(&auth, server.auth_method);
                curl_easy_setopt(curl, CURLOPT_LOGIN_OPTIONS, auth.buf);
                strbuf_release(&auth);
+#endif
        }
 
        if (!server.use_ssl)