default: add unit packages (#26)

default.nix

@@ -9,9 +9,9 @@
 { pkgs ? import <nixpkgs> { } }:
 
 import ./pkgs/top-level/all-packages.nix { inherit pkgs; }
-  // {
+// {
   # The `lib`, `modules`, and `overlay` names are special
   lib = import ./lib { inherit pkgs; }; # functions
   modules = import ./modules; # NixOS modules
   overlays = import ./overlays; # nixpkgs overlays
-}
+} // import ./callUnitRoot.nix { inherit pkgs; }