[llvm] [llvm-otool] Add -a option to print archive headers (PR #189411)

[Daniel Rodríguez Troitiño via llvm-commits]

https://github.com/drodriguez requested changes to this pull request.

The summary/commit message seems to be completely empty. Can we add some content explaining the changes (I understand it is for compatibility with Apple's `otool`, but a casual observer might find the empty summary confusing).

https://github.com/llvm/llvm-project/pull/189411