anchor.diff:        # honors $LIBRARY_PATH.  See
         # http://python.net/crew/theller/ctypes/reference.html#id1 .
         wrapProgram "$out/bin/impressive" \
  -         --prefix PATH ":" "${xpdf}" \
  +         --prefix PATH ":" "${xpdf}/bin" \
            --prefix PYTHONPATH ":" \
                     ${lib.concatStringsSep ":"
                        (map (path:
                               path + "/lib/${python.libPrefix}/site-packages")
                             [ pillow pyopengl pygame setuptools ])} \
  -         --prefix LIBRARY_PATH ":" "${lib.makeLibraryPath [ mesa freeglut ]}"
  +         --prefix LIBRARY_PATH ":" "${lib.makeLibraryPath [ mesa freeglut SDL ]}"
       '';
   
       meta = {
  
positive.code: 
      src = fetchurl {
        url = "mirror://sourceforge/impressive/Impressive-${version}.tar.gz";
        sha256 = "0fz1zahxlfjang53wn06svy4s4aw28c79v24gwadvjvv3h1g5wam";
      };
  
      # Note: We need to have `setuptools' in the path to be able to use
  
negative.code: { fetchurl, stdenv, python2Packages, makeWrapper, lib
  , xpdf, mesa, SDL, freeglut }:
  
  let
    inherit (python2Packages) python pyopengl pygame setuptools pillow;
    version = "0.11.1";
  in stdenv.mkDerivation {
      # This project was formerly known as KeyJNote.
      # See http://keyj.s2000.ws/?p=77 for details.
  