Second, if I'm using "-w", I'm typically interested in errors if I write fishy code, not because some third-party library I just updated made a small change to its API. I don't see where the advantage would be in conflating the two things.
You don't get 'warning' deprecations from third-party code, you get them from the compiler when you use a feature that is on its way to being deprecated. Usually because it's fishy.
