CURLOPT_KEYPASSWD(3) on macOS

The text 2262e6a3446f, 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.

set passphrase to private key

CURLOPT_KEYPASSWD(3) on macOS now