* GNUmakefile (configure): Use the variable.

* INSTALL.REPO: Document the variable (bug#51965).

These are generated files that were once kept in the repository.
When they were removed from the repository, as a half-way measure
they were only deleted by "extraclean", but this was never
necessary and was not a proper use of that rule.
* admin/charsets/Makefile.in (gen-clean): New phony target.
(maintainer-clean): Delete generated files.
* admin/grammars/Makefile.in (gen-clean): New phony target.
(maintainer-clean): Delete generated files.
* admin/unidata/Makefile.in (gen-clean): New phony target.
(maintainer-clean): Delete generated files.
* leim/Makefile.in (gen-clean): New phony target.
(maintainer-clean): Delete generated files.
* GNUmakefile: Doc fix.

* GNUmakefile: Add description of 'extraclean'.

* Makefile.in (extraclean_dirs): Add lwlib.

* lwlib/Makefile.in (clean mostlyclean extraclean): Add
'extraclean' target.

* lisp/Makefile.in (extraclean): Remove ${loaddefs}, not just
${LOADDEFS}.  Delete all backup and autosave files.

Run "TZ=UTC0 admin/update-copyright".

Run "TZ=UTC0 admin/update-copyright $(git ls-files)".

This mostly changes http: to https: in URLs.  It also updates
some URLs that have moved, removes some URLs that no longer
work, recommends against using procmail (procmail.org no
longer works), and removes some mentions of the
no-longer-existing Gmane, LPF and VTW.
It doesn't update all URLs, just the ones I had time for.
* GNUmakefile (help):
* admin/admin.el (manual-doctype-string):
* admin/charsets/Makefile.in (${charsetdir}/ALTERNATIVNYJ.map):
* admin/charsets/mapconv:
* lisp/net/soap-client.el (soap-create-envelope):
* lisp/org/org.el (org-doi-server-url):
* lisp/textmodes/bibtex.el (bibtex-generate-url-list):
Prefer https: to http: un URLs.

* GNUmakefile: Add new "help" target that shows a brief summary of
common make targets.  (Bug#12411)
* INSTALL
* etc/NEWS: Announce it.

Run 'TZ=UTC0 admin/update-copyright $(git ls-files)'.