[compiler-rt] [llvm] Reapply "compiler-rt: Introduce runtime functions for emulated PAC." (PR #148094)

[Peter Collingbourne via llvm-commits]

pcc wrote:

Hmm. I had intended to fix this with 1ddb909a422853bd8e2692a8d369b45d62cec3e5 but now I realize that this clearly won't work because signals aren't a thing on Windows and the commands run on the host. This one should fix it I hope: 968d38d1d7d9de2d5717457876bba2663b36f620

https://github.com/llvm/llvm-project/pull/148094