Chase wlroots master branch up to a289f81

[m-col]

Rather than following the wlroots' devs changelog of changes that could break compositors, I'm instead taking the approach of chasing their master branch in our wlroots-next branch.

I accidentally pushed to this repo rather than my fork's wlroots-next branch, but to get the code review without force pushing over that history I figured I'd raise this PR against main but instead of merging we can close it and continue working on this branch. Then I'll raise future PRs against this branch to update in step with wlroots.

The commit history matches the order of wlroots' git history so linking commits here with wlroots commits is straight forward. Commit messages are in the form of (wlroots <wlroots commit hash>) <original wlroots commit message> if they do correspond to wlroots commits.

The changes so far catch up to wlroots master as of writing so it's a big batch (sorry!) but obviously future updates will be more incremental.

[m-col]

wlroots master but not 0.17 workflows run fine. I suspect because of master's continue-on-error here: https://github.com/flacjacket/pywlroots/blob/main/.github/workflows/ci.yml#L121

What was the purpose of that? the main code and the tinywl work fine so i think it's just a bit of fiddling in .github that's remaining before this can be merged

[flacjacket]

The continue-on-error for master lets us try to build it, but it won't show as an error if it can't build, which will be the case once a breaking change is made there.