[libunwind] [libunwind] Add GCS support for AArch64 (PR #99335)

[John Brawn via cfe-commits]

john-brawn-arm wrote:

> LGTM. Sorry for the delay.
> 
> Q: Is there a way to play with the GCS feature in a VM? Do you have setup instructions?

https://git.yoctoproject.org/meta-arm/log/?h=testing/gcs is a demonstration embedded linux that support GCS, including an emulator capable of running it. https://git.yoctoproject.org/meta-arm/tree/meta-arm-gcs/README?h=testing/gcs is the instructions for building and running it.

https://github.com/llvm/llvm-project/pull/99335