org-ctags.el: Protect shell specials in directory name

* lisp/org-ctags.el (org-ctags-create-tags): Escape shell specials.

Directory name (the argument or `default-directory') may contain various
characters interpreted by shell.  Effects may vary from just incorrect
actual path to execution of a command embedded into path.  Neither
double nor single quotes is a safe way to use directory name in shell
commands since the name may contain these characters.

A follow-up to
Martin Marshall. [PATCH] `org-ctags-create-tags` creates empty TAGS file.
Fri, 09 Feb 2024 18:57:48 -0500.
<https://list.orgmode.org/87h6ihgphf.fsf@martinmarshall.com>

lisp/org-ctags.el

@@ -504,18 +504,21 @@ function may take several seconds to finish if the directory or
 its subdirectories contain large numbers of taggable files."
   (interactive)
   (cl-assert (buffer-file-name))
-  (let ((dir-name (or directory-name
-                      (file-name-directory (buffer-file-name))))
+  (let ((dir-name (shell-quote-argument
+                   (expand-file-name
+                    (if directory-name
+                        (file-name-as-directory directory-name)
+                      (file-name-directory (buffer-file-name))))))
         (exitcode nil))
     (save-excursion
       (setq exitcode
             (shell-command
              (format (concat "%s --langdef=orgmode --langmap=orgmode:.org "
-                             "--regex-orgmode=\"%s\" -f \"%s\" -e -R %s")
+                             "--regex-orgmode=%s -f %sTAGS -e -R %s*")
                      org-ctags-path-to-ctags
-                     org-ctags-tag-regexp
-                     (expand-file-name (concat dir-name "/TAGS"))
-                     (expand-file-name (concat (shell-quote-argument dir-name) "/*")))))
+                     (shell-quote-argument org-ctags-tag-regexp)
+                     dir-name
+                     dir-name)))
       (cond
        ((eql 0 exitcode)
         (setq-local org-ctags-tag-list