anchor.diff:  
     propagatedBuildInputs =
       [ bzip2 freetype libjpeg libpng libtiff libxml2 zlib librsvg
  -    libtool jasper libX11 ] ++ stdenv.lib.optional (ghostscript != null && stdenv.system != "x86_64-darwin") ghostscript;
  +      libtool jasper libX11
  +    ] ++ stdenv.lib.optional (ghostscript != null && stdenv.system != "x86_64-darwin") ghostscript;
   
  -  buildInputs = [ tetex graphviz ];
  +  buildInputs = [ tetex ];
   
     postInstall = ''(cd "$out/include" && ln -s ImageMagick* ImageMagick)'';
   
  
positive.code: , fetchurl
  , bzip2
  , freetype
  , graphviz
  , ghostscript ? null
  , libjpeg
  , libpng
  
negative.code:     sha256 = "1bpj8676mph5cvyjsdgf27i6yg2iw9iskk5c69mvpxkyawgjw1vg";
    };
  
    enableParallelBuilding = true;
  
    preConfigure = if tetex != null then
      ''
        export DVIDecodeDelegate=${tetex}/bin/dvips
  