[lld] [llvm] [lld][MachO] Add ARM64e pointer authentication linking support (PR #188378)

[Oliver Hunt via llvm-commits]

================

----------------
ojhunt wrote:

I'd kind of prefer InStruct (I think that's what `in` is but it took a while to track this down) to handle this with something like `InStruct::AddGOTEntry(sim, isauthgot)`, but that implies a structural change outside of the scope of this PR

https://github.com/llvm/llvm-project/pull/188378