curl_version(3) on macOS

The text 6b3ca02b3e18, 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.

returns the libcurl version string

curl_version(3) on macOS now