anchor.diff:         (declare (dynamic-extent #',thunk))
          (call-with-/dev/random #',thunk))))
   
  -(defvar */dev/random-stream* nil)
  -
   (defvar *real-random-p* :use-features
     "Control whether we use /dev/random or /dev/urandom.
   See documentation for `real-random-p'.")
  
positive.code: (defun random-byte ()
    "(cl:random 256)"
    (random 256))
  
  (defun random-integer (limit)
    "(cl:random LIMIT)"
  
negative.code: (defun /dev/random-path ()
    (if (real-random-p) "/dev/random" "/dev/urandom"))
  
  (defvar */dev/random-stream* nil)
  (defvar *remainder*)
  (defvar *remainder-bits*)
  
  (defun call-with-/dev/random (thunk)
    "Helper function for `with-dev/random'."
    (if */dev/random-stream*
        (funcall thunk */dev/random-stream*)
        (with-open-file (s (/dev/random-path) :element-type '(unsigned-byte 8))
          (let ((*/dev/random-stream* s)
                (*remainder* 0)
                (*remainder-bits* 0))
            (funcall thunk s)))))
  
  (defun random-byte ()
  