anchor.diff:                 ,(when *foreign-function-list*
                     `(export ',*foreign-function-list*))
                  ,(when *foreign-extern-list*
  -                  `(export ',*foreign-extern-list*)))))))))
  +                  `(export ',*foreign-extern-list*))
  +               ,(when *foreign-const-list*
  +                  `(export ',*foreign-const-list*)))))))))
  
positive.code: (defmethod parse-form (form (tag (eql 'const)))
    (alist-bind (name value) form
      (let ((sym (foreign-type-symbol name :cconst *package*)))
        (if (stringp value)
            `(defvar ,sym ,value)
            `(defconstant ,sym ,value)))))
  
negative.code: (defvar *foreign-record-list* nil)
  (defvar *foreign-function-list* nil)
  (defvar *foreign-extern-list* nil)
  (defvar *foreign-const-list* nil)
  (defvar *foreign-symbol-exceptions* nil)
  
   ;; Collecting symbols
  
  (defmacro collecting-symbols (&body body)
    `(let (*foreign-record-list* *foreign-function-list* *foreign-extern-list*
           *foreign-const-list*)
       ,@body))
  
  