Don't use nix-channels

lib.nix

@@ -0,0 +1,33 @@
+{
+  findImport = name:
+    let
+      localpath = ./.. + "/${name}";
+      importpath = ./imports + "/${name}";
+    in
+    if builtins.pathExists localpath then
+      localpath
+    else if builtins.pathExists importpath then
+      (import importpath)
+    else (abort "couldn't find import ${name}");
+
+  mkSystem = { nixpkgs, system ? "x86_64-linux", rev ? "git", extraModules ? [ ], ... }:
+    let
+      pkgs = import (nixpkgs) {
+        inherit (machine.config.nixpkgs) config overlays;
+      };
+      nixPath = pkgs.runCommand "nix-path"
+        { } ''
+        mkdir -p $out
+        ln -s "${nixpkgs}" $out/nixpkgs
+      '';
+      machine = import "${nixpkgs}/nixos/lib/eval-config.nix" {
+        inherit system;
+        modules = [
+          ({ ... }: {
+            nix.nixPath = [ "${nixPath}" ];
+          })
+        ] ++ extraModules;
+      };
+    in
+    machine;
+}