anchor.diff:  
     configurePhase = "makeFlags=PREFIX=$out";
   
  +  postInstall = ''
  +    wrapProgram "$out/bin/i3-save-tree" --prefix PERL5LIB ":" "$PERL5LIB"
  +  '';
  +
     meta = with stdenv.lib; {
       description = "A tiling window manager";
       homepage    = "http://i3wm.org";
  
positive.code: { fetchurl, stdenv, which, pkgconfig, libxcb, xcbutilkeysyms, xcbutil,
    xcbutilwm, libstartup_notification, libX11, pcre, libev, yajl,
    xcb-util-cursor, coreutils, perl, pango, perlPackages, xdummy }:
  
  stdenv.mkDerivation rec {
    name = "i3-${version}";
  
negative.code:   };
  
    buildInputs = [
      which pkgconfig makeWrapper libxcb xcbutilkeysyms xcbutil xcbutilwm
      libstartup_notification libX11 pcre libev yajl xcb-util-cursor perl pango
      perlPackages.AnyEventI3 perlPackages.X11XCB perlPackages.IPCRun
      perlPackages.ExtUtilsPkgConfig perlPackages.TestMore perlPackages.InlineC
  