anchor.diff:      (setf (fifo-head fifo) 0
             (fifo-tail fifo) 0)
       ;; Signal the cvar to wake any waiting FIFO-PUSH calls.
  -    (condition-notify (fifo-cv fifo))))
  +    (condition-notify (fifo-cv fifo) t)))
  
positive.code:   (reset-ephemeral-thread sys.int::*snapshot-thread* #'snapshot-thread :sleeping)
    (reset-ephemeral-thread sys.int::*pager-thread* #'pager-thread :runnable)
    (reset-ephemeral-thread sys.int::*disk-io-thread* #'disk-thread :runnable)
    (condition-notify *world-stop-cvar*))
  
  (defun wake-thread (thread)
    "Wake a sleeping thread."
  
negative.code:       (with-mutex (*world-stop-lock*)
          ;; Release the dogs!
          (setf *world-stopper* nil)
          (condition-notify *world-stop-cvar* t)))))
  
  (defmacro with-world-stopped (&body body)
    `(call-with-world-stopped (dx-lambda () ,@body)))
  