title: how to supress popup window from emacs programatically?
body: <p>For example, I have this setup in my .emacs</p>
  
  <pre><code>(defun gtags-create-or-update ()
    "Create or update the gnu global tag file."
    (interactive)
    (if (y-or-n-p-with-timeout
         (format "Run gtags to create/update tag file for code at %s (default no)? "
                 default-directory)
         5 nil) ; default - no run
        (unless (= 0 (call-process "global" nil nil nil " -p")) ; tagfile doesn't exist?
            (let ((olddir default-directory)
                  (topdir (read-directory-name
                           "gtags: top of source tree: " default-directory)))
              (cd topdir)
              (shell-command "gtags -v")
              ;; (shell-command "gtags &amp;&amp; echo 'created tagfile'")
              (cd olddir)) ; restore
          ;;  tagfile already exists; update it
          (shell-command "global -uv"))))
  ;; (shell-command "global -u &amp;&amp; echo 'updated tagfile'")))
  
  (add-hook 'c-mode-common-hook
    (lambda ()
      (require 'gtags)
      (gtags-mode t)
      (gtags-create-or-update)))
  </code></pre>
  
  <p>When I run <code>gtags-create-or-update</code> explicitly, emacs prompt in the minibuffer to ask me whether to create/update tag files. However, when I open a c/cpp file, it always pops up a GUI window ask me yes or no, which is super annoying. I am wondering why this is happening.</p>