CURLOPT_ERRORBUFFER.3: Fix example, escape backslashes

  /* perform the request */

  res = curl_easy_perform(curl);

  /* if the request did not complete correctly, show the error information.

  if no detailed error information was written to errbuf show the more generic

  information from curl_easy_strerror instead.

  /* if the request did not complete correctly, show the error

  information. if no detailed error information was written to errbuf

  show the more generic information from curl_easy_strerror instead.

  */

  if(res != CURLE_OK) {

    size_t len = strlen(errbuf);

    fprintf(stderr, "\nlibcurl: (%d) ", res);

    fprintf(stderr, "\\nlibcurl: (%d) ", res);

    if(len)

      fprintf(stderr, "%s%s", errbuf, ((errbuf[len - 1] != '\n') ? "\n" : ""));

      fprintf(stderr, "%s%s", errbuf,

              ((errbuf[len - 1] != '\\n') ? "\\n" : ""));

    else

      fprintf(stderr, "%s\n", curl_easy_strerror(res));

      fprintf(stderr, "%s\\n", curl_easy_strerror(res));

  }

}

.fi