[llvm] [LLVM][Clang][AArch64] Implement AArch64 build attributes (PR #123990)

[Peter Smith via llvm-commits]

smithp35 wrote:

I've posted https://github.com/llvm/llvm-project/pull/125838 to discard .ARM.attributes sections in LLD. This will be the right thing to do for all but relocatable links so it can be built upon by @sivan-shani , who is working on full support in LLD right now.

https://github.com/llvm/llvm-project/pull/123990