[llvm] [Sema, Lex, Parse] Preprocessor embed in C and C++ (and Obj-C and Obj-C++ by-proxy) (PR #68620)

[Shafik Yaghmour via llvm-commits]

shafik wrote:

> FWIW, I spoke offline with the original author of the PR and he said that he's fine with me picking up the changes and carrying the review forward.
> 
> Because I don't know of any better way to commandeer a patch in GitHub, I'll probably grab the changes, get them into my own fork, and then recreate the PR to get the review started. Whenever we get ready to land the PR, @ThePhD will be credited as a co-author.

So just to clarify, we should wait till you post a follow-up review before commenting, to avoid fragmenting the discussion.

https://github.com/llvm/llvm-project/pull/68620