NixOS/nixpkgs — pull request #1106 by ocharles (2013-10-21 16:11:28+00:00)
Title: services.redshift: New service

The certainly does the job for me, but it might need a little more polishing. For example - should it depend on `display-manager`? Should it even run with systemd? What about the hard-coding of `DISPLAY`? These are questions I am unable to answer, so hopefully someone can help me.