anchor.diff:  ;;; balanced
   
   (defmacro with-recursive-lock-held ((place) &body body)
  -  `(mt:with-lock (,place) ,@body))
  +  `(mt:with-mutex-lock (,place) ,@body))
   
   ;;; Resource contention: condition variables
   
  
positive.code:   (mt:list-threads))
  
  (defun interrupt-thread (thread function)
    (mt:thread-interrupt thread function))
  
  (defun destroy-thread (thread)
    (signal-error-if-current-thread thread)
    (mt:thread-kill thread))
  
  (defun thread-alive-p (thread)
    (mt:thread-active-p thread))
  
negative.code:   (mt:mutex-unlock lock))
  
  (defmacro with-lock-held ((place) &body body)
    `(mt:with-mutex-lock (,place) ,@body))
  
  (defun make-recursive-lock (&optional name)
    (mt:make-mutex :name name :recursive-p t))
  