anchor.diff:         list)
       (push current list)))
   
  +(defun terminate-thread (thread)
  +  (establish-thread-foothold
  +   thread
  +   (lambda ()
  +     (throw 'terminate-thread nil))))
  +
  +(defmacro dx-lambda (lambda-list &body body)
  +  `(flet ((dx-lambda ,lambda-list ,@body))
  +     (declare (dynamic-extent #'dx-lambda))
  +     #'dx-lambda))
  +
  +;;; Foothold management.
  +
   (defun %pop-foothold ()
     (safe-without-interrupts ()
       (pop (thread-pending-footholds (current-thread)))))
  
positive.code: (defun (setf thread-stack-pointer) (value thread)
    (setf (thread-state-rsp thread) value))
  
  (defconstant +thread-mv-slots-start+ 32)
  (defconstant +thread-mv-slots-end+ 128)
  (defconstant +thread-tls-slots-start+ 128)
  (defconstant +thread-tls-slots-end+ 427)
  (defconstant +thread-interrupt-save-area+ 427)
  (defconstant +thread-fx-save-area+ 447)
  
  (defmacro with-thread-lock ((thread) &body body)
    (let ((sym (gensym "thread")))
  
negative.code:                                    old (cons function old))
           (return)))))
  
  ;;; Stopping the world.
  ;;; WITH-WORLD-STOPPED and WITH-PSEUDO-ATOMIC work together as a sort-of global
  ;;; reader/writer lock over the whole system.
  
  