nix-shell updated to be compatible with LTS14.4 (#254)

nix/src.json

@@ -1,6 +1,6 @@
 {
  "owner": "NixOS",
  "repo": "nixpkgs",
- "rev": "dbb9f8818af7cf2ea91b89f7d80a8fb1800cbfb5",
- "sha256": "1i8lsiscjzq066p02a5c7azjrvqxqkz6dipzkkyhh9rmhgs1aca3"
+ "rev": "8731aaaf8b30888bc24994096db830993090d7c4",
+ "sha256": "1hcc89rxi47nb0mpk05nl9rbbb04kfw97xfydhpmmgh57yrp3zqa"
 }

nix/update

@@ -7,7 +7,7 @@ set -euo pipefail
 
 cd "$(dirname "$0")" || exit 1
 
-branch=release-18.04
+branch=release-19.09
 
 owner=NixOS
 repo=nixpkgs

shell.nix

@@ -11,8 +11,8 @@ let
  pkgs = import nixpkgs {};
 in
  pkgs.haskell.lib.buildStackProject {
- # Either use specified GHC or use GHC 8.6.4 (which we need for LTS 13.13)
- ghc = if isNull ghc then pkgs.haskell.compiler.ghc864 else ghc;
+ # Either use specified GHC or use GHC 8.6.5 (which we need for LTS 14.4)
+ ghc = if isNull ghc then pkgs.haskell.compiler.ghc865 else ghc;
  extraArgs = "--system-ghc";
  name = "tf-env";
  buildInputs = with pkgs; [ snappy zlib protobuf libtensorflow ];