anchor.diff:  { stdenv, fetchFromGitHub, fetchpatch, lib
  -, autoconf, automake, gnum4, libtool, git, perl, gnulib, uthash, pkgconfig, gettext
  +, autoconf, automake, gnum4, libtool, perl, gnulib, uthash, pkgconfig, gettext
   , python, freetype, zlib, glib, libungif, libpng, libjpeg, libtiff, libxml2, pango
   , withGTK ? false, gtk2
   , withPython ? true
  
positive.code:   })];
    patchFlags = "-p0";
  
    # FIXME: git isn't really used, but configuration fails without it
    buildInputs = [
      git autoconf automake gnum4 libtool perl pkgconfig gettext uthash
      python freetype zlib glib libungif libpng libjpeg libtiff libxml2
    ]
      ++ lib.optionals withGTK [ gtk2 pango ]
  
negative.code:     ++ lib.optional withGTK "--enable-gtk2-use"
      ++ lib.optional (!withGTK) "--without-x";
  
    # work-around: git isn't really used, but configuration fails without it
    preConfigure = ''
      export GIT="$(type -P true)"
      cp -r "${gnulib}" ./gnulib
      chmod +w -R ./gnulib
      ./bootstrap --skip-git --gnulib-srcdir=./gnulib
  