[Nix-dev] environment.systemPackages

[Benjamin Franksen]

I tried to adapt the example for environment.systemPackages in the NixOS 
manual, but nixos-rebuild complains that pkgs is not defined. This is what I 
tried:

nixos# cat /etc/nixos/configuration.nix
{
  boot.initrd.kernelModules = [  "ata_piix" ];
  boot.kernelModules = [  ];
  boot.loader.grub.device = "/dev/sda";

  fileSystems = [ { device = "/dev/sda1"; mountPoint = "/"; fsType = "ext3"; 
} ];

  environment.systemPackages = [ pkgs.zsh ];

  nix.maxJobs = 1;

  services.ntp.servers = [ "charm.acc.bessy.de" ];

  services.xserver.videoDriver = "vesa";
  services.xserver.enable = true;
  services.xserver.desktopManager.kde4.enable = true;
  services.xserver.displayManager.kdm.enable = true;
  services.xserver.autorun = true;
  services.xserver.desktopManager.default = "kde4";
  services.xserver.windowManager.xmonad.enable = true;
}

How can I make the pkgs variable visible here?

Cheers
Ben