ligthdm.md

This is all assuming you are on 17.03 as I haven't tested my changes against unstable. Leave a comment here if you have any questions.

fork https://github.com/NixOS/nixpkgs on github

clone it locally:

$ git clone [email protected]:erlandsona/nixpkgs.git
$ cd nixpkgs

get channel information via git:

$ git remote add channels git://github.com/NixOS/nixpkgs-channels.git
$ git remote update channels

set up new local branch based on 17.03:

$ git checkout -b local-17.03 channels/nixos-17.03

add a remote for my fork:

$ git remote add pbogdan [email protected]:pbogdan/nixpkgs.git
$ git remote update pbogdan

pick the lightdm changes:
```
$ git cherry-pick c48e9e386374ae4f3b90dbd64c2c934ce8475a36
$ git cherry-pick 89e9f1473553114619738718173f82af19565063
```
the c48e9e386374ae4f3b90dbd64c2c934ce8475a36 commit isn't really required but will save having to resolve a merge conflict manually as it's not in 17.03, see NixOS/nixpkgs#24135

adjust /etc/nixos/configuration.nix with the new options:

services.xserver = {
   ...
   displayManager = {
     lightdm = {
       enable = true;
         greeters = {
           gtk = {
             enable = true;
             cursorTheme = {
               package = pkgs.gnome3.defaultIconTheme;
               name = "Adwaita";
               size = 32;
           };
         };
       };
    };
    ...
  };
};

rebuild the system using your own fork:
```
$ sudo nixos-rebuild switch -I nixpkgs=/home/erlandsona/nixpkgs
```
(adjust the path as needed)

You would need to use -I nixpkgs=/home/erlandsona/nixpkgs whenever your rebuild. If at some point you would want to use your own fork for your user with nix-env you can point to it with nix-env -i somepackage -f ~/nixpkgs/.

If you want to update and get the latest upstream changes from 17.03 you would run:

$ git remote update channels
$ git rebase channels/nixos-17.03

pbogdan/ligthdm.md