anchor.diff:    };
   
     buildInputs = [ fftw qt5.base ];
  -  propagatedBuildInputs = [ boost ];
   
  -  patchPhase = ''
  -    substituteInPlace LibKeyFinder.pro --replace "/usr/local" "$out"
  +  postPatch = ''
  +    substituteInPlace LibKeyFinder.pro \
  +      --replace "/usr/local" "$out" \
  +      --replace "-stdlib=libc++" ""
     '';
   
     configurePhase = ''
  
positive.code: 
    postInstall = ''
      mkdir -p $out/include/keyfinder
      cp *.h $out/include/keyfinder
    '';
  }
  
negative.code: { stdenv, fetchFromGitHub, fftw, qt5 }:
  
  let version = "2.1"; in
  stdenv.mkDerivation {
    name = "libkeyfinder-${version}";
  
    src = fetchFromGitHub {
      sha256 = "07kc0cl6kirgmpdgkgmp6r3yvyf7b1w569z01g8rfl1cig80qdc7";
      rev = "v${version}";
      repo = "libKeyFinder";
      owner = "ibsh";
  