Use (with-no-warnings ...) construct for `date' and `entry'.

lisp/org-agenda.el

@@ -91,8 +91,8 @@
 (defvar org-agenda-buffer-name)
 (defvar org-agenda-overriding-header)
 (defvar org-agenda-title-append nil)
-(defvar entry)
-(defvar date)
+(with-no-warnings (defvar entry)) ;; unprefixed, from calendar.el
+(with-no-warnings (defvar date))  ;; unprefixed, from calendar.el
 (defvar org-agenda-undo-list)
 (defvar org-agenda-pending-undo-list)
 (defvar original-date) ; dynamically scoped, calendar.el does scope this

lisp/org-bbdb.el

@@ -122,7 +122,7 @@
 (declare-function calendar-leap-year-p "calendar" (year))
 (declare-function diary-ordinal-suffix "diary-lib" (n))
 
-(defvar date)   ;; dynamically scoped from Org
+(with-no-warnings (defvar date)) ;; unprefixed, from calendar.el
 
 ;; Customization