anchor.diff:  
     meta = with stdenv.lib; {
       description = "A flat theme with transparent elements for GTK 3, GTK 2 and Gnome-Shell";
  -    homepage = https://github.com/horst3180/arc-theme;
  -    license = licenses.gpl3;
  -    platforms = platforms.unix;
  +    homepage    = https://github.com/horst3180/arc-theme;
  +    license     = licenses.gpl3;
       maintainers = with maintainers; [ simonvandel romildo ];
  +    platforms   = platforms.unix;
     };
   }
  
positive.code: 
    preferLocalBuild = true;
  
    configureFlags = [ "--disable-unity" ];
  
    postInstall = ''
      mkdir -p $out/share/plank/themes
  
negative.code: { stdenv, fetchFromGitHub, autoreconfHook, pkgconfig, gnome3, gtk-engine-murrine }:
  
  let
    # treat versions newer than 3.22 as 3.22
    gnomeVersion = if stdenv.lib.versionOlder "3.22" gnome3.version then "3.22" else gnome3.version;
    pname = "arc-theme";
  
  in stdenv.mkDerivation rec {
    name = "${pname}-${version}";
    version = "2017-05-12";
  
    src = fetchFromGitHub {
      owner  = "horst3180";
      repo   = pname;
      rev    = "8290cb813f157a22e64ae58ac3dfb5983b0416e6";
      sha256 = "1lxiw5iq9n62xzs0fks572c5vkz202jigndxaankxb44wcgn9zyf";
    };
  
  