curl_easy_setopt (curl, CURLOPT_WRITEFUNCTION, nginx_curl_callback);
curl_easy_setopt (curl, CURLOPT_USERAGENT, PACKAGE_NAME"/"PACKAGE_VERSION);
curl_easy_setopt (curl, CURLOPT_ERRORBUFFER, nginx_curl_error);
if (user != NULL)
{
curl_easy_setopt (curl, CURLOPT_WRITEFUNCTION, nginx_curl_callback);
curl_easy_setopt (curl, CURLOPT_USERAGENT, PACKAGE_NAME"/"PACKAGE_VERSION);
curl_easy_setopt (curl, CURLOPT_ERRORBUFFER, nginx_curl_error);
if (user != NULL)
{