dbus-dev.tcz
   Xorg-7.7-dev.tcz
      libxcb-dev.tcz
         libxcb.tcz
   dbus.tcz
      Xorg-7.7-lib.tcz
         libxcb.tcz
      expat2.tcz
      libxcb.tcz
   expat2-dev.tcz
      expat2.tcz
   libxcb-dev.tcz
      libxcb.tcz