CURLOPT_URL(3) on macOS

The text f03d968ca580, as macOS 10.12.5, macOS 10.12.4, macOS 10.12.3, macOS 10.12.2, macOS 10.12.1, macOS 10.12 shipped it.

provide the URL to use in the request

CURLOPT_URL(3) on macOS now