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.
[Bjørn Forsman <bjorn.forsman@gmail.com>:
- use types.lines instead of types.string. The former joins strings
with "\n" and the latter with "" (and is deprecated).
]
