anchor.diff:    cmakeFlags = ["-DWITH_TESTS=ON"];
   
     doCheck = true;
  +
  +  postPatch = ''
  +    substituteInPlace docopt.pc.in \
  +      --replace "@CMAKE_INSTALL_PREFIX@/@CMAKE_INSTALL_LIBDIR@" \
  +                "@CMAKE_INSTALL_LIBDIR@"
  +  '';
   
     checkPhase = "LD_LIBRARY_PATH=$(pwd) python ./run_tests";
   
  
positive.code:     maintainers = with maintainers; [ knedlsepp ];
    };
  }
  
  
negative.code: { stdenv, fetchFromGitHub, cmake, python }:
  
  stdenv.mkDerivation rec {
    version = "0.6.3";
    pname = "docopt.cpp";
  
    src = fetchFromGitHub {
      owner = "docopt";
      repo = "docopt.cpp";
      rev = "v${version}";
      sha256 = "0cz3vv7g5snfbsqcf3q8bmd6kv5qp84gj3avwkn4vl00krw13bl7";
    };
  
    nativeBuildInputs = [ cmake python ];
  