anchor.diff:      (%forward-ikeyword #'defsys:unbind #'call-next-method
                          system-name definition-name))
     (:method ((system-name symbol) definition-name)
  -    (defsys:unbind (defsys:locate 'defsys:system system-name)
  +    (defsys:unbind (defsys:locate *root-system* system-name)
                      definition-name))
     (:method ((system hash-table-mixin) definition-name)
       (setf (gethash definition-name (slot-value system '%hash)) nil)))
  
positive.code:                                     system-name definition-name :errorp errorp)
                   new-definition))
    (:method (new-definition (system-name symbol) definition-name &key (errorp nil))
      (setf (defsys:locate (defsys:locate 'defsys:system system-name)
                           definition-name
                           :errorp errorp)
            new-definition))
  
negative.code:   (:method ((system-name symbol) definition-name environment args
              &rest options &key &allow-other-keys)
      (apply #'defsys:expand-definition
             (defsys:locate *root-system* system-name)
             definition-name environment args options)))
  
  (defmacro defsys:define ((kind definition-name &body options)
  