It has been deprecated since at least macOS 10.9 and fully removed in 10.12.
I am unsure if we should remove it only in 2.8. But you cannot build blender with it supported when using a modern xcode version anyway so I would tend towards just removing it also for 2.79 if that ever happens.
Reviewers: mont29, dfelinto, juicyfruit, brecht
Reviewed By: mont29, brecht
Subscribers: Blendify, brecht
Maniphest Tasks: T52807
Differential Revision: https://developer.blender.org/D2333