anchor.diff:      url = "http://oss.oetiker.ch/rrdtool/pub/${name}.tar.gz";
       sha256 = "1xm6ikzx8iaa6r7v292k8s7srkzhnifamp1szkimgmh5ki26sa1s";
     };
  -  buildInputs = [ gettext perl pkgconfig libxml2 pango cairo groff ];
  +  buildInputs = [ gettext perl pkgconfig libxml2 pango cairo groff ]
  +    ++ stdenv.lib.optional stdenv.isDarwin tcl-8_5;
     
     postInstall = ''
       # for munin and rrdtool support
  
positive.code:     homepage = http://oss.oetiker.ch/rrdtool/;
      description = "High performance logging in Round Robin Databases";
      license = licenses.gpl2;
      platforms = platforms.linux;
      maintainers = with maintainers; [ pSub ];
    };
  }
  
negative.code: { fetchurl, stdenv, gettext, perl, pkgconfig, libxml2, pango, cairo, groff
  , tcl-8_5 }:
  
  stdenv.mkDerivation rec {
    name = "rrdtool-1.5.5";
  