I have a question that's unrelated to your commit, but maybe you can help me understand it anyway. The line above emties testToolDepends, presumably to avoid the dependency on utillinux. Now, when the test suite is disabled by means of dontCheck, then those dependencies shouldn't be evaluated anyway, right? So in my mind, messing with testToolDepends on Darwin is unnecessary. Can you confirm that this is the case? Because if it where, when this override could be simplified even further.

You're correct, but I left it there for future as someday the tests may pass on hakyll again. I'd say it's better to be explicit here about utillinux.