/*
 * call-seq:
 *   easy.last_effective_url                          => "http://some.url" or nil
 *
 * Retrieve the last effective URL used by this instance.
 * This is the URL used in the last +perform+ call,
 * and may differ from the value of easy.url.
 */
static VALUE ruby_curl_easy_last_effective_url_get(VALUE self) {