curl_version_info(3) on macOS

The text a9ac9556ecde, 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 run-time libcurl version info

curl_version_info(3) on macOS now