anchor.diff:    system_config_printer = import ../tools/misc/system-config-printer {
       inherit stdenv fetchurl perl perlXMLParser autoconf automake intltool gettext desktop_file_utils;
     };
  -  
  +
     tcpdump = import ../tools/networking/tcpdump {
       inherit fetchurl stdenv libpcap;
     };
  
positive.code:   pyqt4 = import ../development/python-modules/pyqt {
      inherit stdenv fetchurl python sip qt4;
    };
    
    pyx = import ../development/python-modules/pyx {
      inherit fetchurl stdenv python makeWrapper;
    };
  
negative.code:   pycups = import ../development/python-modules/pycups {
      inherit stdenv fetchurl python cups;
    };
  
    pygame = import ../development/python-modules/pygame {
      inherit fetchurl stdenv python pkgconfig SDL SDL_image
        SDL_mixer SDL_ttf numeric;
  