* fixes for the Qt plugin compilation under Debian

 * heavy butchering in the CSS and DVD ioctl code to put all architecture-
   dependent code in dvd_ioctl.c

 * added almost fully-functional /dev/dvd driver for MacOS X in
   extras/DVDioctl; to build it:

    % cd extras/DVDioctl
    % pbxbuild
    % kextload build/DVDioctl.kext # note: kextload has to be run as root

   be aware that the license for the DVDioctl kernel extension is
   not GPL but APSL, because I borrowed some code from the Darwin kernel.