[clang] [RFC] Initial implementation of P2719 (PR #113510)

[Oliver Hunt via cfe-commits]

ojhunt wrote:

> > Could anyone with a windows machine see if you can work out what is happening with the windows test failure? I don't understand why the tests are failing on the windows bot as it seems like it should simply fail everything (e.g. windows driver is going wrong) or it should work
> 
> It looks like the latest commit did pass on Windows, so this may be redundant but it also passes locally on my Windows machine.

Yeah, it took some time to work out the issue and it was basically just the standard "I wrote tests without a sufficiently explicit target triple" :D

https://github.com/llvm/llvm-project/pull/113510