Before enabling dconf in Home Manager, dconf must be enabled in system
config.
Otherwise it will fail like this:
```
$ home-manager switch
Starting Home Manager activation
Activating checkFilesChanged
Activating checkLinkTargets
Activating writeBoundary
Activating installPackages
replacing old 'home-manager-path'
installing 'home-manager-path'
Activating dconfSettings
error: GDBus.Error:org.freedesktop.systemd1.NoSuchUnit: Unit dconf.service not found.
```
In the manual:
* Add chapter Nix Flakes
* Add links to sections of chapter "Using Home Manager"
In README.md:
* Remove section "Nix Flakes"
* Add manual reference at the buttom of section "Installation"
Specifically,
- include system-wide Nixpkgs channel so `NIX_PATH` solution also
works on multi-user installations;
- additionally link to Nix Discourse reply for more information on
`NIX_PATH`; and
- remove note about relog on NixOS since all the channels in
`~/.nix-defexpr/channels/` are included by default, so the Home
Manager channel should be picked up automatically.
Currently, dot directories and XDG base directories are used
inconsistently in the Home Manager option declarations. This creates
ambiguity for the user as to where the location of the file should be
albeit this is rarely encountered in practice as it is sufficient to
read upstream documentation. The rationale is to make declarations
consistent and make a clear distinction between hardcoded and modular
specifications.
References to ~/.config in relevant nixpkgs modules were untouched as
the location is hardcoded upstream[1]. Furthermore, modules of
programs which do not follow XDG specifications were also untouched.
Generalization of tilde(~) expansions to $HOME were also considered,
however there isn't sufficient rationale despite the use of $HOME
being more universal. The expansion is standardized in POSIX[2] and is
essentially portable across all shells, thus there is no pragmatic
value to introducing the change.
[1] https://github.com/nixos/nixpkgs/blob/master/pkgs/top-level/impure.nix
[2] https://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_01
If the keyboard configuration is an empty set, don't run the setxkbmap
service.
The default values for all keyboard options are null or empty so long
as the state version is set to 19.09 or higher (21.05 being the latest
version).
Specifically, instead of
services.dbus.packages = with pkgs; [ gnome.dconf ];
we now recommend
programs.dconf.enable = true;
which does the same and more.
The docs implied that fish was not really supported, but if fish is
managed by Home Manager, the generated config does use fenv to source
the session-vars file. Update the installation instructions and FAQ to
mention that fish does work, and mention fenv in the README.