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

[Peter Smith via llvm-commits]

smithp35 wrote:

Repeating a comment on the LLD patch just in case its useful in this context.

FWIW I've just checked GNU ld. It already has some code for SHT_AARCH64_ATTRIBUTES as the section name has been reserved since the initial AArch64 ABI. This will remove (I've tested it) the SHT_AARCH64_ATTRIBUTES section from the output so we don't need to worry about GNU ld.
https://github.com/bminor/binutils-gdb/blob/master/bfd/elfnn-aarch64.c#L8383

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