diff --git a/default.nix b/default.nix
--- a/default.nix
+++ b/default.nix
@@ -5,14 +5,15 @@
 # "shell.nix" so that it does not have to clutter this file.
 
 args@
-{ pythonPackages ? "python27Packages"
+{ system ? builtins.currentSystem
+, pythonPackages ? "python27Packages"
 , pythonExternalOverrides ? self: super: {}
 , doCheck ? false
 , ...
 }:
 
 let
-  pkgs_ = (import <nixpkgs> {});
+  pkgs_ = args.pkgs or (import <nixpkgs> { inherit system; });
 in
 
 let
diff --git a/release.nix b/release.nix
--- a/release.nix
+++ b/release.nix
@@ -1,12 +1,20 @@
 # This file defines how to "build" for packaging.
 
-{ doCheck ? true
+{ pkgs ? import <nixpkgs> {}
+, system ? builtins.currentSystem
+, doCheck ? false
 }:
 
 let
   vcsserver = import ./default.nix {
     inherit
-      doCheck;
+      doCheck
+      system;
+
+    # disable checkPhase for build
+    checkPhase = ''
+    '';
+
   };
 
 in {