curl_share_setopt(3) on macOS

The text 410df4045ea9, as Mac OS X 10.8.5, Mac OS X 10.8.4, Mac OS X 10.8.3, Mac OS X 10.8.2, Mac OS X 10.8.1, Mac OS X 10.8 shipped it.

Set options for a shared object

curl_share_setopt(3) on macOS now