- We no longer support setting the CURLOPT_URL option from inside a callback

such as the CURLOPT_SSL_CTX_FUNCTION one treat that as if it was a Location:
  following. The patch that introduced this feature was done for 7.11.0, but
  this code and functionality has been broken since about 7.15.4 (March 2006)
  with the introduction of non-blocking OpenSSL "connects".

  It was a hack to begin with and since it doesn't work and hasn't worked
  correctly for a long time and nobody has even noticed, I consider it a very
  suitable subject for plain removal. And so it was done.

lib/url.c

@@ -1481,8 +1481,6 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
     result = setstropt(&data->set.str[STRING_SET_URL],
                             va_arg(param, char *));
     data->change.url = data->set.str[STRING_SET_URL];
-    if(data->change.url)
-      data->change.url_changed = TRUE;
     break;
   case CURLOPT_PORT:
     /*