curl_easy_setopt(3) on macOS

The text 05d88abfde40, as Mac OS X 10.6.8, Mac OS X 10.6.7, Mac OS X 10.6.6, Mac OS X 10.6.5, Mac OS X 10.6.4, Mac OS X 10.6.3 shipped it.

set options for a curl easy handle

curl_easy_setopt(3) on macOS now