[lld] [lld][AArch64][ELF][PAC] Support AUTH relocations and AUTH ELF marking (PR #72714)

[Daniil Kovalev via llvm-commits]

kovdan01 wrote:

> https://github.com/access-softek/musl/tree/dkovalev/pauth-code-drop may need an update

@MaskRay This musl implementation is just a proof-of-concept to ensure that AUTH relocs work properly and to have ability to actually execute pauth-enabled code. In terms of this PoC, reading (platform,version) values from GNU property and faulting on their mismatch in different DSOs is considered out of scope - it does not give that much value in terms of testing the toolchain itself. So, we only have crucial features implemented - particularly, handling AUTH relocs.

https://github.com/llvm/llvm-project/pull/72714