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

[Oskar Wirga via llvm-commits]

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

----------------
oskarwirga wrote:

> Might be worth to break up this PR into smaller ones.

I am not opposed to the idea but these changes are quite interdependent and decomposing this would result in functionally dead code, at least for the first couple PRs

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