I had tried to build a bunch of different codebases (git, bash, gcc, curl etc.) before trying busybox, and I'd never seen code like that before. Plus that error came alongside a compiler error in my patch that took a long time to debug, so it was a memorable surprise :)

Would you consider a code pattern like that to be common? What other codebases apart from busybox have it? If there are many examples, I might spend some time trying to update my patch to handle patterns of that kind.