Merge pull request #926 from bbarker/nix

adding nix shell for building and using HIE

Author: alanz

shell.nix

@@ -0,0 +1,16 @@
+with import <nixpkgs> {};
+stdenv.mkDerivation {
+  name = "haskell-ide-engine";
+  buildInputs = [
+    gmp
+    zlib
+    ncurses
+
+    haskellPackages.cabal-install
+  ];
+  src = null;
+  shellHook = ''
+    export LD_LIBRARY_PATH=${gmp}/lib:${zlib}/lib:${ncurses}/lib
+    export PATH=$PATH:$HOME/.local/bin
+  '';
+}