Use gnulib maintainer-makefile module.
* m4/gnulib-cache.m4: Import maintainer-makefile module.
* cfg.mk (local-checks-to-skip): Drop changelog-check; add
sc_cast_of_x_alloc_return_value.
(gnulib_dir, gnu_rel_host, url_dir_list): Delete; provided by
maint.mk.
(config_h_header, old_NEWS_hash): New macros.
* .prev-version: New file.
* maint.mk: Remove from version control; use gnulib instead.
* .gitignore: Update.
* HACKING: Update.
Signed-off-by: Eric Blake <ebb9@byu.net>
(cherry picked from commit
260383467b3ae57f2cb3c6821718b99fdf278c4b)