anchor.diff:    ];
   
     libPath = lib.makeLibraryPath libs;
  +
  +  stretchly =
  +    stdenv.mkDerivation rec {
  +      pname = "stretchly";
  +      version = "0.21.0";
  +
  +      src = fetchurl {
  +        url = "https://github.com/hovancik/stretchly/releases/download/v${version}/stretchly-${version}.tar.xz";
  +        sha256 = "1gyyr22xq8s4miiacs8wqhp7lxnwvkvlwhngnq8671l62s6iyjzl";
  +      };
  +
  +      nativeBuildInputs = [
  +        wrapGAppsHook
  +        coreutils
  +      ];
  +
  +      buildInputs = libs;
  +
  +      dontPatchELF = true;
  +      dontBuild = true;
  +      dontConfigure = true;
  +
  +      installPhase = ''
  +        mkdir -p $out/bin $out/lib/stretchly
  +        cp -r ./* $out/lib/stretchly/
  +        ln -s $out/lib/stretchly/stretchly $out/bin/
  +      '';
  +
  +      preFixup = ''
  +        patchelf --set-rpath "${libPath}" $out/lib/stretchly/libffmpeg.so
  +        patchelf --set-rpath "${libPath}" $out/lib/stretchly/libEGL.so
  +        patchelf --set-rpath "${libPath}" $out/lib/stretchly/libGLESv2.so
  +        patchelf --set-rpath "${libPath}" $out/lib/stretchly/swiftshader/libEGL.so
  +        patchelf --set-rpath "${libPath}" $out/lib/stretchly/swiftshader/libGLESv2.so
  +
  +        patchelf \
  +          --set-rpath "$out/lib/stretchly:${libPath}" \
  +          --set-interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
  +          $out/lib/stretchly/stretchly
  +
  +        patchelf \
  +          --set-rpath "$out/lib/stretchly:${libPath}" \
  +          --set-interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
  +          $out/lib/stretchly/chrome-sandbox
  +      '';
  +
  +      meta = with stdenv.lib; {
  +        description = "A break time reminder app";
  +        longDescription = ''
  +          stretchly is a cross-platform electron app that reminds you to take
  +          breaks when working on your computer. By default, it runs in your tray
  +          and displays a reminder window containing an idea for a microbreak for 20
  +          seconds every 10 minutes. Every 30 minutes, it displays a window
  +          containing an idea for a longer 5 minute break.
  +        '';
  +        homepage = https://hovancik.net/stretchly;
  +        downloadPage = https://hovancik.net/stretchly/downloads/;
  +        license = licenses.bsd2;
  +        maintainers = with maintainers; [ cdepillabout ];
  +        platforms = platforms.linux;
  +      };
  +    };
  +
   in
   
  -stdenv.mkDerivation rec {
  -  pname = "stretchly";
  -  version = "0.19.1";
  +buildFHSUserEnv {
  +  inherit (stretchly) meta;
   
  -  src = fetchurl {
  -    url = "https://github.com/hovancik/stretchly/releases/download/v${version}/stretchly-${version}.tar.xz";
  -    sha256 = "1q2wxfqs8qv9b1rfh5lhmyp3rrgdl05m6ihsgkxlgp0yzi07afz8";
  -  };
  +  name = "stretchly";
   
  -  nativeBuildInputs = [
  -    wrapGAppsHook
  +  targetPkgs = pkgs: [
  +     stretchly
     ];
   
  -  buildInputs = libs;
  +  runScript = "stretchly";
   
  -  dontPatchELF = true;
  -  dontBuild = true;
  -  dontConfigure = true;
  +  passthru = {
  +    updateScript = writeScript "update-stretchly" ''
  +      #!${runtimeShell}
   
  -  installPhase = ''
  -    mkdir -p $out/bin $out/lib/stretchly
  -    cp -r ./* $out/lib/stretchly/
  -    ln -s $out/lib/stretchly/libffmpeg.so $out/lib/
  -    ln -s $out/lib/stretchly/libnode.so $out/lib/
  -    ln -s $out/lib/stretchly/stretchly $out/bin/
  -  '';
  +      set -eu -o pipefail
   
  -  preFixup = ''
  -    patchelf --set-rpath "${libPath}" $out/lib/stretchly/libffmpeg.so
  -    patchelf --set-rpath "${libPath}" $out/lib/stretchly/libnode.so
  +      # get the latest release version
  +      latest_version=$(curl -s https://api.github.com/repos/hovancik/stretchly/releases/latest | jq --raw-output .tag_name | sed -e 's/^v//')
   
  -    patchelf \
  -      --set-rpath "$out/lib/stretchly:${libPath}" \
  -      --set-interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" \
  -      $out/lib/stretchly/stretchly
  -  '';
  +      echo "updating to $latest_version..."
   
  -  meta = with stdenv.lib; {
  -    description = "A break time reminder app";
  -    longDescription = ''
  -      stretchly is a cross-platform electron app that reminds you to take
  -      breaks when working on your computer. By default, it runs in your tray
  -      and displays a reminder window containing an idea for a microbreak for 20
  -      seconds every 10 minutes. Every 30 minutes, it displays a window
  -      containing an idea for a longer 5 minute break.
  +      ${common-updater-scripts}/bin/update-source-version stretchly.passthru.stretchlyWrapped "$latest_version"
       '';
  -    homepage = https://hovancik.net/stretchly;
  -    downloadPage = https://hovancik.net/stretchly/downloads/;
  -    license = licenses.bsd2;
  -    maintainers = with maintainers; [ cdepillabout ];
  -    platforms = platforms.linux;
  +
  +    stretchlyWrapped = stretchly;
     };
   }
  
positive.code: , libnotify
  , libpciaccess
  , libpng12
  , libxcb
  , nspr
  , nss
  , pango
  , pciutils
  , pulseaudio
  , stdenv
  , udev
  , wrapGAppsHook
  }:
  
  let
  
negative.code:     libnotify
      libpciaccess
      libpng12
      libuuid
      libxcb
      nspr
      nss
  