[llvm] Support: unlock Windows API support, switch to Windows 10 RS1+ APIs (PR #102240)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

> also, we do not explicitly document what versions of Windows we support, or any OS for that matter, and I think that documentation should be created so users know what to expect

I was pretty sure we had such a statement written down somewhere - I remember reading it when I got started in LLVM many years ago (stating that we require Windows 7, both for running LLVM itself, and for the runtimes to run on), but I can't find that now. Maybe it was more implicit after all...

https://github.com/llvm/llvm-project/pull/102240