anchor.diff:  
     cmakeFlags = [
       "-DPYTHON_DESIRED=${stdenv.lib.substring 0 1 python.pythonVersion}"
  -  ];
  +  ] ++ stdenv.lib.optional stdenv.isDarwin "-DWITH_ZCHUNK=OFF";
   
     postFixup = ''
       moveToOutput "lib/${python.libPrefix}" "$py"
  
positive.code:     description = "Library providing C and Python (libcURL like) API for downloading linux repository metadata and packages";
      homepage = "https://rpm-software-management.github.io/librepo/";
      license = licenses.lgpl2Plus;
      platforms = platforms.linux;
      maintainers = with maintainers; [ copumpkin ];
    };
  }
  
negative.code:     libxml2
      glib
      openssl
      curl
      check
      gpgme
    ]
    # zchunk currently has issues compiling in darwin, fine in linux
    ++ stdenv.lib.optional stdenv.isLinux zchunk;
  
    # librepo/fastestmirror.h includes curl/curl.h, and pkg-config specfile refers to others in here
    propagatedBuildInputs = [
  