anchor.diff:  , gmpxx
   , ncurses5
   , gnustep
  +, libffi
   }:
   stdenv.mkDerivation rec {
     pname = "hopper";
  
positive.code:     libbsd
      python27
      gmpxx
  
      ncurses5
      gnustep.libobjc
    ];
  
negative.code:       $sourceRoot/opt/hopper-${rev}/lib/libpthread_workqueue.so* \
        $out/lib
  
      # we already ship libffi.so.7
      ln -s ${lib.getLib libffi}/lib/libffi.so $out/lib/libffi.so.6
  
      cp -r $sourceRoot/usr/share $out
  
      runHook postInstall
  