import gnulib dirent module

import gnulib dirent module

This imports the gnulib dirent module.  It doesn't make any other
changes to gdb.

2013-11-18  Tom Tromey  <tromey@redhat.com>

	* gnulib/update-gnulib.sh (IMPORTED_GNULIB_MODULES): Add dirent.
	* gnulib/aclocal.m4: Update.
	* gnulib/config.in: Update.
	* gnulib/configure: Update.
	* gnulib/import/Makefile.am: Update.
	* gnulib/import/Makefile.in: Update.
	* gnulib/import/dirent.in.h: New.
	* gnulib/import/m4/dirent_h.m4: New.
	* gnulib/import/m4/gnulib-cache.m4: Update.
	* gnulib/import/m4/gnulib-comp.m4: Update.