[clang] [C23] Handle type compatibility for enumerations better (PR #150282)

[Tobias Hieta via cfe-commits]

tru wrote:

> > @AaronBallman can you squash this? (release procedure is a bit different so we prefer to get it pre-squashed).
> 
> Sure, but I'm not certain we should have a different merge strategy for main vs release branches so I'd like to understand more about what's driving this. Are we planning on switching all contributions to squashing first? Or is this a temporary thing for release branches?

We can't use the github squash and merge workflow on the release branch, it makes it so the PR and the commit is not correctly linked. So we use a script to merge PR's from the release branch instead, this script does a straight rebase merge, so when we have multiple commits that are iterative work in a release pr we ask the backporters to squash them. I can also do it if you prefer.

This limitation is only for the release branches and we hope that the bug we have with the github merge button will go away at some point.

https://github.com/llvm/llvm-project/pull/150282