anchor.diff:  { lib, stdenv
   , fetchFromGitHub
   , sassc
  -, autoreconfHook
  +, meson
  +, ninja
   , pkg-config
   , gtk3
  +, glib
   , gnome
   , gtk-engine-murrine
   , optipng
  
positive.code:     gtk-engine-murrine
    ];
  
    enableParallelBuilding = true;
  
    preBuild = ''
      # Shut up inkscape's warnings about creating profile directory
      export HOME="$NIX_BUILD_ROOT"
    '';
  
    configureFlags = [
      "--with-cinnamon=${cinnamon.cinnamon-common.version}"
      "--with-gnome-shell=${gnome.gnome-shell.version}"
      "--disable-unity"
    ];
  
    postInstall = ''
      install -Dm644 -t $out/share/doc/${pname} AUTHORS *.md
    '';
  
    meta = with lib; {
      description = "Flat theme with transparent elements for GTK 3, GTK 2 and Gnome Shell";
  
negative.code: 
  stdenv.mkDerivation rec {
    pname = "arc-theme";
    version = "20210412";
  
    src = fetchFromGitHub {
      owner = "jnsh";
      repo = pname;
      rev = version;
      sha256 = "sha256-BNJirtBtdWsIzQfsJsZzg1zFbJEzZPq1j2qZ+1QjRH8=";
    };
  
    nativeBuildInputs = [
      meson
      ninja
      pkg-config
      sassc
      optipng
      inkscape
      gtk3
      glib # for glib-compile-resources
    ];
  
    propagatedUserEnvPkgs = [
  