[Ecls-list] Latest changes

[Juan Jose Garcia-Ripoll]

 - ECL now implements weak pointers. The interface is
	(ext:make-weak-pointer value) => weak-pointer
	(ext:weak-pointer-value weak-pointer) => value
   and it defines a new built-in type, EXT:WEAK-POINTER

> (defparameter *a* (ext:make-weak-pointer (cons 2 2)))

*A*
> (dotimes (i 10)
    (format t "~&Pass #~D weak pointer value: ~A" i
(ext:weak-pointer-value *a*))
    (dotimes (j 100000) (cons 1 1))
     (ext:gc t))

Pass #0 weak pointer value: (2 . 2)
Pass #1 weak pointer value: NIL
Pass #2 weak pointer value: NIL
Pass #3 weak pointer value: NIL
Pass #4 weak pointer value: NIL
Pass #5 weak pointer value: NIL
Pass #6 weak pointer value: NIL
Pass #7 weak pointer value: NIL
Pass #8 weak pointer value: NIL
Pass #9 weak pointer value: NIL
NIL