anchor.diff:      # to be a generic solution here.
       find $(echo ${stdenv.lib.makeLibraryPath [
           glib libX11 pango cairo gtk2 gdk_pixbuf gtkglext
  -        mesa libXmu libXt libICE libSM ]} | sed -e 's#:# #g') -name \*.so.\* > $TMPDIR/so.lst
  +        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);
  
positive.code:     wrapProgram $out/bin/factor --prefix LD_LIBRARY_PATH : \
        "${stdenv.lib.makeLibraryPath [ glib
          libX11 pango cairo gtk2 gdk_pixbuf gtkglext
          mesa 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
  
negative.code:   nativeBuildInputs = [ pkgconfig ];
    buildInputs = [ git rlwrap curl perl makeWrapper
      libX11 pango cairo gtk2 gdk_pixbuf gtkglext
      mesa_glu libXmu libXt libICE libSM ];
  
    buildPhase = ''
      make $(bash ./build-support/factor.sh make-target) GIT_LABEL=heads/master-${rev}
  