How do I enable debug output?

[Udo Thiel]

Forgive me if this question seems to be trivial, but after an hour of googling I still couldn't find an answer, so I hope some kind person could help me. I'd like to see verbose or maybe trace output from YapDB. I can see from the sources that this requires a DEBUG build of the framework, but how do I do this and add it to my project? I use carthage.

Thanks in advance.