[clang] [Clang] Rework creating offloading toolchains (PR #125556)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> > This broke compilation with Xcode Clang 12 (roughly corresponding to upstream Clang 10):
> 
> It's not limited to that, I was seeing it too, it's breaking on 32-bit targets with older compilers that do not implicitly move between non-identical types. I've pushed the obvious fix.

Thanks for fixing that.

https://github.com/llvm/llvm-project/pull/125556