anchor.diff:  
     qmakeFlags = [
       "COMMUNI_INSTALL_PREFIX=${placeholder "out"}"
  -    "COMMUNI_INSTALL_BINS=${placeholder "out"}/bin"
       "COMMUNI_INSTALL_PLUGINS=${placeholder "out"}/lib/communi/plugins"
       "COMMUNI_INSTALL_ICONS=${placeholder "out"}/share/icons/hicolor"
       "COMMUNI_INSTALL_DESKTOP=${placeholder "out"}/share/applications"
       "COMMUNI_INSTALL_THEMES=${placeholder "out"}/share/communi/themes"
  +    (if stdenv.isDarwin
  +      then [ "COMMUNI_INSTALL_BINS=${placeholder "out"}/Applications" ]
  +      else [ "COMMUNI_INSTALL_BINS=${placeholder "out"}/bin" ])
     ];
   
  -  postInstall = lib.optionalString stdenv.isLinux ''
  +  postInstall = if stdenv.isDarwin then ''
  +    # Nix qmake does not add the bundle rpath by default.
  +    install_name_tool \
  +      -add_rpath @executable_path/../Frameworks \
  +      $out/Applications/Communi.app/Contents/MacOS/Communi
  +
  +    wrapQtApp $out/Applications/Communi.app/Contents/MacOS/Communi
  +  '' else ''
       substituteInPlace "$out/share/applications/communi.desktop" \
         --replace "/usr/bin" "$out/bin"
     '';
  
positive.code: { fetchgit, libcommuni, qtbase, qmake, lib, stdenv }:
  
  stdenv.mkDerivation rec {
    pname = "communi";
  
negative.code:     fetchSubmodules = true;
    };
  
    nativeBuildInputs = [ qmake ]
      ++ lib.optional stdenv.isDarwin wrapQtAppsHook;
  
    buildInputs = [ libcommuni qtbase ];
  
  