Fully static stage1 compiler on windows

[Sahnvour]

Fixes #3391.

This doesn't enable linking debug zig with release llvm yet but I still plan to do it soon.

[mikdusan]

if it's desirable to build Release mode on vs2019 we can change /Ob2 → /Ob1 to get around compiler bug.

[andrewrk]

Next steps:

• Update https://github.com/ziglang/zig/wiki/How-to-build-LLVM,-libclang,-and-liblld-from-source#windows correspondingly
• Update https://ziglang.org/deps/llvm+clang-9.0.0-win64-msvc-release.tar.xz
• Rebuild this branch in the CI and make sure it works

[Sahnvour]

@andrewrk wiki updated, I can provide a static build of llvm+clang if you wish.

[andrewrk]

Thanks @Sahnvour. I started a build based on the new instructions. It will probably be ~12 hours before the new tarball is in place.

I can provide a static build of llvm+clang if you wish.

I'll be happy to set up you the bomb with S3 permissions at some point so that you can do this. The UI for that is annoying though and I don't have enough patience today for it, so for now I'll take care of uploading this tarball.

[andrewrk]

Continued in a branch in this repository here: #3467