This change makes use of the `extend` function inside `lib` to inject
a new `hm` field containing the Home Manager library functions. This
simplifies use of the Home Manager library in the modules and reduces
the risk of accidental infinite recursion.
PR #994
Given an inner type, the former function generates a type that expect
DAG option values. The latter function is only present to temporarily
allow the `programs.ssh.matchBlocks` to keep accepting list values.
Because `extraPackages` and `overrides` expect functions as values it
has not been possible to perform merges. This adds suitable types for
these options that allow reasonable merging.
Naïm Favier
Robert Helgesson
Sebastian Zivota
ivann
Jonas Holst Damtoft