[clang] [lld] [llvm] [MTE] Improve memtag support for non-Android AArch64 targets (PR #183275)

[Florian Mayer via cfe-commits]

fmayer wrote:

> > > Thanks for putting up llvm/clang/lld together to make the full picture clear, but when you are ready for a real review, ensure lld changes are extracted to a separate patch.
> > 
> > 
> > @MaskRay I have three commits, one for lld, one for the clang Driver and one for llvm CodeGen. Is this ok or do you want me to break things up more?
> 
> Unfortunately this repo is configured to only allow ["Squash and merge"](https://maskray.me/blog/2023-09-09-reflections-on-llvm-switch-to-github-pull-requests#commit-message). The merged patch gets a single commit. In this case we do want separate commits, which can only be achieved with multiple PRs.

Which will make the new approach of using the same flags for Android and non-Android a bit harder, because now between the commits LLD and the driver will be out of sync

https://github.com/llvm/llvm-project/pull/183275