Since the 4.2.8 upgrade, ntpd is broken on NixOS:
Dec 28 19:06:54 hagbard ntpd[27723]: giving up resolving host 1.nixos.pool.ntp.org: Servname not supported for ai_socktype (-8)
This appears to be because DNS resolution doesn't work in chroots
anymore (due to /etc being missing). So disable chroots for now. It's
probably better to use systemd's containment facilities anyway.
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
