Comment 1 for bug 721135

I'm in 1.0.49 and the message is slightly reworded:

CL-USER> (compile nil (lambda ()
                        (destructuring-bind (&optional (x nil xp)) '()
                          (declare (ignore x xp))
                          nil)))
; in: COMPILE ()
; (IGNORE X XP)
;
; caught STYLE-WARNING:
; IGNORE declaration for an unknown variable: XP
;
; compilation unit finished
; caught 1 STYLE-WARNING condition