org-ctags: Silence byte-compiler

* lisp/org-ctags.el (y-or-n-minibuffer): Remove function.
(org-ctags-find-tag):
(org-ctags-find-tag-interactive): Use `xref-find-definitions' instead of
`find-tag'.

lisp/org-compat.el

@@ -540,7 +540,7 @@ Implements `file-equal-p' for older emacsen and XEmacs."
     (/= (- (point-max) (point-min)) (buffer-size))))
 
 ;; As of Emacs 25.1, `outline-mode` functions are under the 'outline-'
-;; prefix.
+;; prefix and `find-tag` is replaced with `xref-find-definition`.
 (when (< emacs-major-version 25)
   (defalias 'outline-show-all 'show-all)
   (defalias 'outline-hide-subtree 'hide-subtree)
@@ -548,7 +548,8 @@ Implements `file-equal-p' for older emacsen and XEmacs."
   (defalias 'outline-show-branches 'show-branches)
   (defalias 'outline-show-entry 'show-entry)
   (defalias 'outline-hide-entry 'hide-entry)
-  (defalias 'outline-hide-sublevels 'hide-sublevels))
+  (defalias 'outline-hide-sublevels 'hide-sublevels)
+  (defalias 'xref-find-definitions 'find-tag))
 
 (defmacro org-with-silent-modifications (&rest body)
   (if (fboundp 'with-silent-modifications)

lisp/org-ctags.el

@@ -273,11 +273,6 @@ Return the list."
   (replace-regexp-in-string (regexp-quote search) replace string t t))
 
 
-(defun y-or-n-minibuffer (prompt)
-  (let ((use-dialog-box nil))
-    (y-or-n-p prompt)))
-
-
 ;;; Internal functions =======================================================
 
 
@@ -302,12 +297,12 @@ The new topic will be titled NAME (or TITLE if supplied)."
 ;;;; Misc interoperability with etags system =================================
 
 
-(defadvice find-tag (before org-ctags-set-org-mark-before-finding-tag
-			    activate compile)
+(defadvice xref-find-definitions
+    (before org-ctags-set-org-mark-before-finding-tag activate compile)
   "Before trying to find a tag, save our current position on org mark ring."
   (save-excursion
-    (if (and (derived-mode-p 'org-mode) org-ctags-enabled-p)
-        (org-mark-ring-push))))
+    (when (and (derived-mode-p 'org-mode) org-ctags-enabled-p)
+      (org-mark-ring-push))))
 
 
 
@@ -359,7 +354,7 @@ visit the file and location where the tag is found."
         (old-pnt (point-marker))
         (old-mark (copy-marker (mark-marker))))
     (condition-case nil
-        (progn (find-tag name)
+        (progn (xref-find-definitions name)
                t)
       (error
        ;; only restore old location if find-tag raises error
@@ -528,7 +523,7 @@ a new topic."
        ((member tag org-ctags-tag-list)
         ;; Existing tag
         (push tag org-ctags-find-tag-history)
-        (find-tag tag))
+        (xref-find-definitions tag))
        (t
         ;; New tag
         (run-hook-with-args-until-success