[clang] [Clang] Make `-Xarch_` handling generic for all toolchains (PR #125421)

[Shilei Tian via cfe-commits]

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@@ -1115,14 +1117,13 @@ def fno_convergent_functions : Flag<["-"], "fno-convergent-functions">,
 
 // Common offloading options
 let Group = offload_Group in {
-def offload_arch_EQ : Joined<["--"], "offload-arch=">, Flags<[NoXarchOption]>,
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shiltian wrote:

If that's the case, what does the `arch` mean in `-Xarch_`? It looks like it means both, which I'm not sure if that's a good idea.

https://github.com/llvm/llvm-project/pull/125421