org.el (org-agenda-file-p): New predicate function.
The new function `org-agenda-file-p' checks if a given file is an org
agenda file. Such a function is very useful in hooks, for example if
you want to export agenda files automatically when saving:
(defun th-org-mode-init ()
;; Update appointments and export to iCalendar when saving.
(when (org-agenda-file-p)
(add-hook 'after-save-hook 'th-org-agenda-to-appt t t)
(add-hook 'after-save-hook 'org-export-icalendar-this-file t t)))
(add-hook 'org-agenda-mode-hook 'th-org-agenda-mode-init)