LKM:
    * Shut down cleanly before rebooting, like Dragos' module did.

    * Accept boot arguments from the userland.

Userland:
    * Load kernel files from Linux file systems, too.  (That can now
      be achieved with `cp bsd /dev/zboot'.)

    * Create crt0.S which defines _start(), so that ld doesn't depend
      on the order of object files.