[lld] [PAC][lld][ELF] Use PAC instructions in PLT header with `-z pac-plt` (PR #116334)

[Jessica Clarke via llvm-commits]

jrtc27 wrote:

In FreeBSD we support multiple RELRO segments within a single object. Perhaps it's time for other implementations to do the same, then LLD can cover whatever set of non-contiguous regions it likes?

https://github.com/llvm/llvm-project/pull/116334