AFAIK, unit tests in separate libraries are not run at all, or did that
change? At least there was a DMD bug report for a long time.

I don't compile vibe as a library, but directly include the source code as a part of my project. That's why :) There has been a discussion about shared libs not working properly, but I guess I should maybe try to build vibe as a static lib? I guess the only thing that would solve is to give me the unittest symbols without actually running the unittests?

Just try to replace version(unittest) with simply unittest.

Just changing that, I get a lot of these: 

source/vibe/concurrency.d(998): Error: found 'private' instead of statement
source/vibe/concurrency.d(1045): Error: unrecognized declaration
source/vibe/concurrency.d(998): Error: found 'private' instead of statement
source/vibe/concurrency.d(1045): Error: unrecognized declaration
source/vibe/concurrency.d(998): Error: found 'private' instead of statement
source/vibe/concurrency.d(1045): Error: unrecognized declaration