Before the profile directory value would point directly to the build
output in the Nix store. Unfortunately this would cause an infinite
loop if the user's configuration directly or indirectly refers to the
profile directory value.
Fixes#1188
It is insufficient to install the packages in `home.packages`, it has
to be `home.path`, which includes configured extra package outputs or
profile commands.
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
This removes the `nixosSubmodule` option in favor of a new option
`submoduleSupport.enable`. This name better indicates that the
submodule mode applies to both NixOS and nix-darwin.
