[clang] [llvm] [llvm] Add triples for managarm (PR #87845)

[Fangrui Song via cfe-commits]

MaskRay wrote:

> [llvm] Add triples for managarm

I suggest that you split the patch into LLVM target triple part and a clang part. That's a convention to support new targets.

https://github.com/llvm/llvm-project/pull/87845