Require em-glob inside 'ls-lisp--dired'. This is necessary to
not break the Emacs build.
See following thread for details:
https://lists.gnu.org/archive/html/emacs-devel/2017-07/msg01083.html
* lisp/ls-lisp.el (dired-goto-next-file)
(dired-read-dir-and-switches, eshell-extended-glob):
Add function declarations.
* lisp/eshell/em-ls.el (dired-goto-next-file): Fix function declaration.