Looks cool! It would probably be useful if there were a way to include dependencies that aren't shipp packages though. Otherwise, since most projects one might depend on right now don't have shipp support, there's a risk of ending up having to use other dependency management solutions alongside shipp, making everything even _more_ complicated rather than simpler, right?

One solution could be to add a `build` and `install` field to the dependency in the project's manifest, I'll see with the feedback if this is worth implementing.

For now, you simply have to add a `shipp.json` file. For SDL I have a repository `shipp-pkg-sdl` (not yet published) which contains only the `shipp.json` file and a submodule to the latest release. It's not perfect, but it works well for now :)