Use ̀org-looking-back' instead of `looking-back' to keep compat with XEmacs

* org-clock.el (org-clock-cancel): Use `org-looking-back'.

* org-pcomplete.el (org-thing-at-point): Ditto.

* org.el (org-timestamp-change): Ditto.

lisp/org-clock.el

@@ -1597,7 +1597,7 @@ UPDOWN tells whether to change 'up or 'down."
   (save-excursion ; Do not replace this with `with-current-buffer'.
     (org-no-warnings (set-buffer (org-clocking-buffer)))
     (goto-char org-clock-marker)
-    (if (looking-back (concat "^[ \t]*" org-clock-string ".*"))
+    (if (org-looking-back (concat "^[ \t]*" org-clock-string ".*"))
 	(progn (delete-region (1- (point-at-bol)) (point-at-eol))
 	       (org-remove-empty-drawer-at "LOGBOOK" (point)))
       (message "Clock gone, cancel the timer anyway")

lisp/org-pcomplete.el

@@ -93,8 +93,8 @@ The return value is a string naming the thing at point."
 	     (skip-chars-backward "[ \t\n]")
 	     ;; org-drawer-regexp matches a whole line but while
 	     ;; looking-back, we just ignore trailing whitespaces
-	     (or (looking-back (substring org-drawer-regexp 0 -1))
-		 (looking-back org-property-re))))
+	     (or (org-looking-back (substring org-drawer-regexp 0 -1))
+		 (org-looking-back org-property-re))))
       (cons "prop" nil))
      ((and (equal (char-before beg1) ?:)
 	   (not (equal (char-after (point-at-bol)) ?*)))

lisp/org.el

@@ -16463,7 +16463,7 @@ in the timestamp determines what will be changed."
 	    (message "No clock to adjust")
 	  (cond ((save-excursion ; fix previous clock?
 		   (re-search-backward org-ts-regexp0 nil t)
-		   (looking-back (concat org-clock-string " \\[")))
+		   (org-looking-back (concat org-clock-string " \\[")))
 		 (setq fixnext 1 clrgx (concat org-ts-regexp0 "\\] =>.*$")))
 		((save-excursion ; fix next clock?
 		   (re-search-backward org-ts-regexp0 nil t)