Replace obsolete variable `buffer-substring-filters'.

* org-agenda.el (org-agenda-mode): Replace obsolete variable
`buffer-substring-filters'.

* org-indent.el (org-indent-mode): Ditto.

lisp/org-agenda.el

@@ -1953,11 +1953,10 @@ 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
-		   (cons (lambda (x)
-                           (set-text-properties 0 (length x) nil x) x)
-			 buffer-substring-filters)))
+  (make-local-variable 'filter-buffer-substring-functions)
+  (add-hook 'filter-buffer-substring-functions
+	    (lambda (fun start end delete)
+	      (substring-no-properties (funcall fun start end delete))))
   (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

@@ -183,9 +183,11 @@ during idle time." nil " Ind" nil
       (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
-		 'org-indent-remove-properties-from-string)
+    (make-local-variable 'filter-buffer-substring-functions)
+    (add-hook 'filter-buffer-substring-functions
+	      (lambda (fun start end delete)
+		(org-indent-remove-properties-from-string
+		 (funcall fun start end delete))))
     (org-add-hook 'after-change-functions 'org-indent-refresh-maybe nil 'local)
     (org-add-hook 'before-change-functions
 		  'org-indent-notify-modified-headline nil 'local)
@@ -209,9 +211,10 @@ during idle time." nil " Ind" nil
     (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
-	  (delq 'org-indent-remove-properties-from-string
-		buffer-substring-filters))
+    (remove-hook 'filter-buffer-substring-functions
+	      (lambda (fun start end delete)
+		(org-indent-remove-properties-from-string
+		 (funcall fun start end delete))))
     (remove-hook 'after-change-functions 'org-indent-refresh-maybe 'local)
     (remove-hook 'before-change-functions
 		 'org-indent-notify-modified-headline 'local)