anchor.diff:      wrapProgram $out/bin/factor --prefix LD_LIBRARY_PATH : \
         "${stdenv.lib.makeLibraryPath [ glib
           libX11 pango cairo gtk2 gdk_pixbuf gtkglext
  -        mesa libXmu libXt libICE libSM ]}"
  +        mesa_glu libXmu libXt libICE libSM ]}"
   
       sed -ie 's#/bin/.factor-wrapped#/lib/factor/factor#g' $out/bin/factor
       mv $out/bin/.factor-wrapped $out/lib/factor/factor
  
positive.code: { stdenv, fetchurl, fetchFromGitHub, glib, glibc, git,
    rlwrap, curl, pkgconfig, perl, makeWrapper, tzdata, ncurses,
    libX11, pango, cairo, gtk2, gdk_pixbuf, gtkglext,
    mesa, libXmu, libXt, libICE, libSM }:
  
  stdenv.mkDerivation rec {
    name = "factor-lang-${version}";
  
negative.code:     # to be a generic solution here.
      find $(echo ${stdenv.lib.makeLibraryPath [
          glib libX11 pango cairo gtk2 gdk_pixbuf gtkglext
          mesa_glu libXmu libXt libICE libSM ]} | sed -e 's#:# #g') -name \*.so.\* > $TMPDIR/so.lst
  
      (echo $(cat $TMPDIR/so.lst | wc -l) "libs found in cache \`/etc/ld.so.cache'";
      for l in $(<$TMPDIR/so.lst);
  