chg:dev: pin nixpkgs version

Author: badmutex

nixpkgs.nix

@@ -0,0 +1,17 @@
+with import <nixpkgs> {};
+
+let
+
+  # to update, run:
+  # nix-prefetch-git git://github.com/NixOS/nixpkgs-channels refs/heads/nixpkgs-unstable
+  src = pkgs.fetchFromGitHub {
+    owner = "NixOS";
+    repo = "nixpkgs-channels";
+    rev = "1fa75a5bb7cdb9f2413d8b20726ce69523bfe4c6"; # 2017/01/02
+    sha256 = "1m20qfgqnbbxzxdkf5x5kvhj996zw6pkikzsyckghxcpwh38ipcv";
+  };
+
+  pinned-pkgs = import src {};
+
+in
+pinned-pkgs

shell.nix

@@ -1,4 +1,4 @@
-with import <nixpkgs> {};
+with import ./nixpkgs.nix;
 
 with pkgs;