anchor.diff:      popd
     '';
   
  +  postInstall = ''
  +    FAV=$out/app/data/flutter_assets/assets/favicon.png
  +    ICO=$out/share/icons
  +
  +    install -D $FAV $ICO/fluffychat.png
  +    mkdir $out/share/applications
  +    cp $desktopItem/share/applications/*.desktop $out/share/applications
  +
  +    for s in 24 32 42 64 128 256 512; do
  +      D=$ICO/hicolor/''${s}x''${s}/apps
  +      mkdir -p $D
  +      convert $FAV -resize ''${s}x''${s} $D/fluffychat.png
  +    done
  +
  +    substituteInPlace $out/share/applications/*.desktop \
  +      --subst-var out
  +  '';
  +
     meta = with lib; {
       description = "Chat with your friends (matrix client)";
       homepage = "https://fluffychat.im/";
  
positive.code: , fetchFromGitLab
  , flutter
  , olm
  }:
  
  flutter.mkFlutterApp rec {
  
negative.code:     hash = "sha256-PJH3jMQc6u9R6Snn+9rNN8t+8kt6l3Xt7zKPbpqj13E=";
    };
  
    desktopItem = makeDesktopItem {
      name = "Fluffychat";
      exec = "@out@/bin/fluffychat";
      icon = "fluffychat";
      desktopName = "Fluffychat";
      genericName = "Chat with your friends (matrix client)";
      categories = "Chat;Network;InstantMessaging;";
    };
  
    buildInputs = [
      olm
    ];
  
    nativeBuildInputs = [
      imagemagick
    ];
  
    flutterExtraFetchCommands = ''
  