[clang] clang: Add BoundArch argument to addClangTargetOptions (PR #196504)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> Another partial solution would be to have TranslateArgs rewrite -mcpu into -mcpu + -m flags for the field, but I figured it would be confusing to have that change midstream (and still has the inconvenience of re-parsing)

It's really only used for weird binding rules in fat binary contexts. I.e. +xnack can link to a gfx942 or something. Unfortunately this goes all the way into the HSA runtime I believe.

https://github.com/llvm/llvm-project/pull/196504