CURLOPT_POSTQUOTE(3) on macOS

The text b5fd666b275a, 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.

(S)FTP commands to run after the transfer

CURLOPT_POSTQUOTE(3) on macOS now