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

[Tobias Hieta via llvm-commits]

tru wrote:

I think we definitely should document it. And FWIW I am fine with a windows 10 requirement since 7 is EOL and I don't think we should hold back if there are good reasons for it. 

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