anchor.diff:  , libxslt
   , xmlto
   
  +, expat
   , libffi
  -, expat
  +, libxml2
   
   , enableDocumentation ? false
   }:
  
positive.code:   buildInputs = [
      expat
      libffi
    ];
  
    configureFlags = [
  
negative.code: 
  stdenv.mkDerivation rec {
    name = "wayland-${version}";
    version = "1.10.0";
  
    src = fetchurl {
      url = "http://wayland.freedesktop.org/releases/${name}.tar.xz";
      sha256 = "1p307ly1yyqjnzn9dbv78yffql2qszn84qk74lwanl3gma8fgxjb";
    };
  
    nativeBuildInputs = [ ]
  