Summary:
The current '--mac' arg builds all supported architectures. This is great when generating release builds but not so much when testing a release for the current architecture.
Not modifying the existing '--mac' arg as to not update our current CI.
Reviewed By: antonk52
Differential Revision: D50497211
fbshipit-source-id: 3e4d9728adc822c48788556e2ea47f4dd1c21b05