anchor.diff:                     ];
   
     makeFlags = [ "GAMEPERM=744" ];
  +  patches = [
  +    # fix regression with bison, merged in master
  +    (fetchpatch {
  +      name = "fix-bison.patch";
  +      url = "https://github.com/UnNetHack/UnNetHack/commit/04f0a3a850a94eb8837ddcef31303968240d1c31.patch";
  +      sha256 = "1zblbwqqz9nx16k6n31wi2hdvz775lvzmkjblmrx18nbm4ylj0n9";
  +    })
  +  ];
   
     enableParallelBuilding = true;
   
  
positive.code:     license = "nethack";
      platforms = platforms.all;
      maintainers = with maintainers; [ abbradar ];
    }; 
  }
  
negative.code: { stdenv, fetchFromGitHub, fetchpatch, utillinux, ncurses, flex, bison }:
  
  stdenv.mkDerivation rec {
    pname = "unnethack";
    version = "5.3.2";
  
    src = fetchFromGitHub {
      name = "UnNetHack";
      owner = "UnNetHack";
      repo = "UnNetHack";
      rev = version;
      sha256 = "1rg0mqyplgn3dfh3wz09a600qxk7aidqw4d84kyiincljvhyb7ps";
    };
  
    buildInputs = [ ncurses ];
  