anchor.diff:        ];
     };
   in releaseTools.nixBuild rec {
  -  name = "hydra-${version}";
  -  version = "2019-03-18";
  +  pname = "hydra";
  +  version = "2019-05-06";
   
     inherit stdenv;
   
     src = fetchFromGitHub {
       owner = "NixOS";
  -    repo = "hydra";
  -    rev = "0721f6623ffb5a4b6a77b499af4eee7d6e4dd6a7";
  -    sha256 = "0b2g2bnbaqpwxx8p81i4gpl4y16i57z5pnjm90fpd0jxnkij3pcg";
  +    repo = pname;
  +    rev = "ff64583d07f046e378a6be596ec0ce7a9e2b7472";
  +    sha256 = "0w88q0saz7si22z3ryim6vdrv9qkwn6l25xfmiapvh5qrnrrdcb9";
     };
   
     buildInputs =
  
positive.code: else
  
  let
    isGreaterNix20 = with lib.versions;
      let
        inherit (nix) version;
        inherit (lib) toInt;
      in major version == "2" && toInt (minor version) >= 1 || toInt (major version) > 2;
  
    perlDeps = buildEnv {
      name = "hydra-perl-deps";
      paths = with perlPackages;
  
negative.code: 
    nativeBuildInputs = [ autoreconfHook pkgconfig ];
  
    patches = [
      (fetchpatch {
        url = "https://github.com/NixOS/hydra/pull/648/commits/4171ab4c4fd576c516dc03ba64d1c7945f769af0.patch";
        sha256 = "1fxa2459kdws6qc419dv4084c1ssmys7kqg4ic7n643kybamsgrx";
  