Automatic merge from submit-queue
Fix make rebuilds for openapi
openapi generates a single file, so its rules can be significantly simpler.
federation generates an empty file which we previously elided, but which triggers deps every build.
This fixes both.
@mbohlool something to think about. Generating a single file means you generate everything every time any tagged package changes. This is not awesome. In practice, it's pretty fast, so maybe just for thinking about - would it be better to generate a file for every tagged package, and only regenerate when needed. The file could self-register a callback or just add some structs to your mega-map.
e808c97943