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

[Aaron Ballman via llvm-commits]

AaronBallman wrote:

> This API was introduced with Windows 10 RS1, and although there are LTSC contracts that allow older versions to be supported still, the mainstream support system has declared this release to be obsoleted. As such, assuming that the OS is at least as new as this is reasonable.

I think this requires an RFC (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).

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