When I script bazel to build a fat objc_library, I appear to lose all build incrementality, probably because it gets reset per ios_cpu. This causes nothing-changed builds to take upwards of a minute where they'd ortherwise take less than a second.

Maybe this overlaps with some other issue or some work on the roadmap that will render this obsolete -- if so, then please close this issue and don't let it distract. :)