Pinning nixpkgs in default.nix

default

let
  config = {
    allowUnfree = true;
  };

  inherit (import <nixpkgs> { }) fetchFromGitHub;

  # Current rev points to 17.09-beta
  pkgs = import (fetchFromGitHub {
    owner  = "NixOS";
    repo   = "nixpkgs";
    rev    = "6a7066eb53685438564dc50362666d0e7f150110";
    sha256 = "1psff8lpp5kmihsg7xv46a0d3rmhsb4kyb9w8r213gn8ggigwg57";
  }) { inherit config; };

  drv = pkgs.haskellPackages.callPackage ./packages.nix { };
in
  drv