Minor issue, however I'm using mountain lion with xcode 4.4 dev preview, and the code doesn't compile out of the box because mach_host.h includes <mach_debug/mach_debug_types.h> - which doesn't exist.
I've removed the import to <mach/mach_host.h> from DDLog.m and the code compiles without it.
Didn't try building on ML yet, and as I'm using quite old version of Cocoa Lumberjack, it might have been updated there already. Will keep this issue open until I address it.
FYI: I started preliminary work on a major redesign, one of the things it does is using completely custom logging mechanism. I'm posting update on experimental branch regularly, so you can check the progress. Note it doesn't produce anything useful at the moment of this writing.
Oh, also take a look at #200 - it's somewhat related.
3.0 doesn't rely on CocoaLumberjack for logging, so while it'll take a while for it to mature enough for releasing, there was no further complaint, so I'm closing this issue.