[clang] [llvm] [LLVM][Clang][Cygwin] Fix building Clang for Cygwin (PR #134494)

[Mateusz Mikuła via cfe-commits]

mati865 wrote:

> These changes mostly look good to me, but it all feels a bit unclear to me still. So I'd appreciate e.g. one or a few sentences in the commit message on each of these commits, to explain a bit about the why/how and how things work in other preexisting environments.

Sure, I'll do that within the next few days.

> Is this for building LLVM/Clang with GCC, or for building LLVM/Clang with Clang?

Both, initially I started with GCC and then added fixes for building with Clang.

> Then secondly, LLVM only allows "squash and merge" merging of PRs - so all these nicely split changes (with individual explanations soon, I'd hope!) would end up all mushed together. So unfortunately, to preserve the info about each of them, they'd need to be filed in separate individual PRs.

I think the descriptions would be preserved if I combined them all into PR description. I've split the commits only to make the review easier.

> Luckily most of these changes don't build on top of each other (even if you might not be able to build things properly unless you have all of them applied at once?), so it should be fairly straightforward to file all those PRs in parallel.

Yeah, this won't build at all without all commits (or most of in case of GCC). So, it's not like there is anything to lose.

https://github.com/llvm/llvm-project/pull/134494