I'm currently learning Vala, and after going through the basics I wanted to do an actual small project to make it more fun. For this, I thought creating a scope for Unity would be perfect (in this case, a Scope for the Music lens to search MPD).
However, documentation on doing something like this is sparse. Therefore, I hope to be able to put together a tutorial on writing a scope in Vala by first going through it myself with the help of Ask Ubuntu.
What I'm currently stuck on, is how to compile my scope in such a way that I can use Unity's library. I've installed libunity-dev (was this necessary?), however, when I try to compile it, I get the following error:
$ valac --pkg libunity ./unity-scope-mpd.vala error: Package `libunity' not found in specified Vala API directories or GObject-Introspection GIR directories Compilation failed: 1 error(s), 0 warning(s)
(Note: I have experience in programming in Java and PHP, but haven't done large projects in the former, so please take that into account in an answer.)