anchor.diff: -{ lib, fetchurl, makeDesktopItem, ffmpeg_3
  +{ lib, fetchurl, makeDesktopItem, ffmpeg
   , qmake, qttools, mkDerivation
   , qtbase, qtdeclarative, qtlocation, qtquickcontrols2, qtwebchannel, qtwebengine
   }:
  
positive.code:   };
  
    installPhase = ''
      install -Dm755 clipgrab $out/bin/clipgrab
      install -Dm644 icon.png $out/share/pixmaps/clipgrab.png
      cp -r ${desktopItem}/share/applications $out/share
    '';
  
    meta = with lib; {
  
negative.code:     url = "https://download.clipgrab.org/${pname}-${version}.tar.gz";
    };
  
    buildInputs = [ ffmpeg qtbase qtdeclarative qtlocation qtquickcontrols2 qtwebchannel qtwebengine ];
    nativeBuildInputs = [ qmake qttools ];
  
    postPatch = lib.optionalString (ffmpeg != null) ''
    substituteInPlace converter_ffmpeg.cpp \
      --replace '"ffmpeg"' '"${ffmpeg.bin}/bin/ffmpeg"' \
      --replace '"ffmpeg ' '"${ffmpeg.bin}/bin/ffmpeg '
    '';
  
    qmakeFlags = [ "clipgrab.pro" ];
  
    desktopItem = makeDesktopItem rec {
      name = "clipgrab";
  