getpgrp(2) on macOS

The text def7787f8ec0, as Mac OS X 10.1.5, Mac OS X 10.1.4, Mac OS X 10.1.3, Mac OS X 10.1.2, Mac OS X 10.1.1, Mac OS X 10.1, Mac OS X 10.0.4, Mac OS X 10.0 shipped it.

get process group

getpgrp(2) on macOS now