Backport commit 20b858ef1 from Emacs

Prefer \... to control chars in .el literals
20b858ef13f8f71fae6cbce5cdac31c4dd130600
Paul Eggert
Thu Mar 29 17:43:08 2018 -0700

lisp/org-ctags.el

@@ -236,7 +236,7 @@ buffer position where the tag is found."
       (with-current-buffer (get-file-buffer tags-file-name)
         (goto-char (point-min))
         (cond
-         ((re-search-forward (format "^.*%s
\\([0-9]+\\),\\([0-9]+\\)$"
+         ((re-search-forward (format "^.*\^?%s\^A\\([0-9]+\\),\\([0-9]+\\)$"
                                      (regexp-quote tag)) nil t)
           (let ((line (string-to-number (match-string 1)))
                 (pos (string-to-number (match-string 2))))
@@ -261,7 +261,7 @@ Return the list."
       (visit-tags-table-buffer 'same)
       (with-current-buffer (get-file-buffer tags-file-name)
         (goto-char (point-min))
-        (while (re-search-forward "^.*\\(.*\\)
\\([0-9]+\\),\\([0-9]+\\)$"
+        (while (re-search-forward "^.*\^?\\(.*\\)\^A\\([0-9]+\\),\\([0-9]+\\)$"
                                   nil t)
           (push (substring-no-properties (match-string 1)) taglist)))
       taglist)))