[clang] [clang][PP] Add extension to predefine target OS macros (PR #74676)

[Mark Adler via cfe-commits]

madler wrote:

> > We have provided a fix for zlib ([madler/zlib#895](https://github.com/madler/zlib/pull/895)) which was accepted by @madler.
> 
> But nowhere released, not even in the repository :(

This should be fixed in the zlib develop branch. Have you tried it?

https://github.com/llvm/llvm-project/pull/74676