Sync files from upstream, and pass 'make syntax-check'.

Sync files from upstream, and pass 'make syntax-check'.

* config/announce-gen: Move...
* build-aux/announce-gen: ...here, and sync from gnulib.
* Makefile.am (EXTRA_DIST): Adjust accordingly.
* cfg.mk (announce_gen): Likewise.
(prev_version_file): Delete, relying on default in maint.mk.
(gpg_key_ID): New macro.
(url_dir_list): Rewrite to match coreutils.
* config/prev-version.txt: Move...
* .prev-version: ...here, and adjust to 2.61.
* build-aux/vc-list-files: Sync from coreutils.
* maint.mk: Resynchronize with coreutils, where possible.
(ME): Remove $(srcdir) from definition.
(CVS): Delete.
(GIT, VC, VC-tag): New macros.
(CVS_LIST, CVS_LIST_EXCEPT): Rename...
(VC_LIST, VC_LIST_EXCEPT): ...to this.
(cvs-tag-check): Delete.
(cvs-diff-check): Rename...
(vc-diff-check): ...to this.
(sc_file_system): Allow FHS acronym.
* doc/autoconf.texi (Particular Functions): Recommend
unconditional <config.h>.
* build-aux/config.guess: Sync from upstream (manually).
* build-aux/config.sub: Likewise.
* build-aux/texinfo.tex: Likewise.
* doc/make-stds.texi: Likewise.
* doc/standards.texi: Likewise.
* .gitattributes: Ignore whitespace problems in upstream files.

Signed-off-by: Eric Blake <ebb9@byu.net>