CURLOPT_SSL_CTX_FUNCTION(3) on macOS

The text 9aa75087d0e1, 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.

SSL context callback for OpenSSL or wolfSSL/CyaSSL

CURLOPT_SSL_CTX_FUNCTION(3) on macOS now