> but there was an article on here not too long ago that was arguing that nearly all os development required old C because choices of the committee would break use cases required under the guise of undefined behavior.

I would guess that you're referring to either "How ISO C became unusable for operating systems development" ([0]) or "How One Word Broke C" ([1]).

[0]: https://arxiv.org/abs/2201.07845 , most recent HN discussion at https://news.ycombinator.com/item?id=30022022

[1]: https://web.archive.org/web/20210307213745/https://news.quel... , HN discussion at https://news.ycombinator.com/item?id=22589657