Silence byte-compiler with a new alias: filter-buffer-substring-functions.

When `filter-buffer-substring-functions' is not a known variable to
Emacs (for versions < 24.1), we alias it to `buffer-substring-filters'.

lisp/org-agenda.el

@@ -1763,11 +1763,11 @@ The following commands are available:
   (org-add-hook 'post-command-hook 'org-agenda-post-command-hook nil 'local)
   (org-add-hook 'pre-command-hook 'org-unhighlight nil 'local)
   ;; Make sure properties are removed when copying text
-  (when (boundp 'buffer-substring-filters)
-    (org-set-local 'buffer-substring-filters
+  (when (boundp 'filter-buffer-substring-functions)
+    (org-set-local 'filter-buffer-substring-functions
 		   (cons (lambda (x)
                            (set-text-properties 0 (length x) nil x) x)
-			 buffer-substring-filters)))
+			 filter-buffer-substring-functions)))
   (unless org-agenda-keep-modes
     (setq org-agenda-follow-mode org-agenda-start-with-follow-mode
 	  org-agenda-entry-text-mode org-agenda-start-with-entry-text-mode

lisp/org-indent.el

@@ -157,8 +157,8 @@ FIXME:  How to update when broken?"
       (org-set-local 'org-hide-leading-stars-before-indent-mode
 		     org-hide-leading-stars)
       (org-set-local 'org-hide-leading-stars t))
-    (make-local-variable 'buffer-substring-filters)
-    (add-to-list 'buffer-substring-filters
+    (make-local-variable 'filter-buffer-substring-functions)
+    (add-to-list 'filter-buffer-substring-functions
 		 'org-indent-remove-properties-from-string)
     (org-add-hook 'org-after-demote-entry-hook
 		  'org-indent-refresh-section nil 'local)
@@ -177,9 +177,9 @@ FIXME:  How to update when broken?"
 	(when (boundp 'org-hide-leading-stars-before-indent-mode)
 	  (org-set-local 'org-hide-leading-stars
 			 org-hide-leading-stars-before-indent-mode))
-	(setq buffer-substring-filters
+	(setq filter-buffer-substring-functions
 	      (delq 'org-indent-remove-properties-from-string
-		    buffer-substring-filters))
+		    filter-buffer-substring-functions))
 	(remove-hook 'org-after-promote-entry-hook
 		     'org-indent-refresh-section 'local)
 	(remove-hook 'org-after-demote-entry-hook

lisp/org-macs.el

@@ -367,6 +367,12 @@ The number of levels is controlled by `org-inlinetask-min-level'"
       (format-seconds string seconds)
     (format-time-string string (seconds-to-time seconds))))
 
+(unless (or (and (>= 24 emacs-major-version)
+		 (>= 1 emacs-minor-version))
+	    (boundp 'filter-buffer-substring-functions))
+  (defvaralias 'filter-buffer-substring-functions
+    'buffer-substring-filters))
+
 (provide 'org-macs)
 
 ;; arch-tag: 7e6a73ce-aac9-4fc0-9b30-ce6f89dc6668