You can see part of my answer here:
https://forums.unrealengine.com/showthread.php?2447-Animation-and-Rigging-Tools-FAQ-Known-Issues-and-Feature-Roadmap&p=72151&viewfull=1#post72151
We’re looking at probably just outsourcing a mac port at this point, as I have no idea when I’ll have the time (currently, I don’t even have a mac to test on!)