- Add new option CURLOPT_HAPPY_EYEBALLS_TIMEOUT to set libcurl's happy
eyeball timeout value.
- Add new optval macro CURL_HET_DEFAULT to represent the default happy
eyeballs timeout value (currently 200 ms).
- Add new tool option --happy-eyeballs-timeout-ms to expose
CURLOPT_HAPPY_EYEBALLS_TIMEOUT. The -ms suffix is used because the
other -timeout options in the tool expect seconds not milliseconds.
Closes https://github.com/curl/curl/pull/2260
