CURLOPT_INTERLEAVEFUNCTION(3) on macOS

The text 508582432a05, 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.

callback function for RTSP interleaved data

CURLOPT_INTERLEAVEFUNCTION(3) on macOS now