* build-aux/gitlog-to-emacslog: Add command-line options.
By default, refuse to remove an existing output file.
* Makefile.in (CHANGELOG): Update default.
(ChangeLog): Do not test for existing file.
(change-history-nocommit): Ensure temp file does not exist.
* Makefile.in (gen_origin): Move to gitlog-to-emacslog.
(emacslog): New variable.
(ChangeLog): Use $emacslog. Don't pass $gen_origin.
(unchanged-history-files): Use $emacslog rather than Makefile.in.
(change-history-nocommit): Store hash in $emacslog.
* build-aux/gitlog-to-emacslog (gen_origin): Move default here.
* admin/update_autogen (changelog_files): Update for the above.
* build-aux/gitlog-to-emacslog: Use ChangeLog.1, not Makefile.in,
for copyright notice prototype, so that we get a proper "coding:"
cookie. Use 'mv -i' to avoid unconditionally overwriting an
existing ChangeLog. Problems reported by Eli Zaretskii in:
http://lists.gnu.org/archive/html/emacs-devel/2015-04/msg00504.html
* .gitignore: Add 'ChangeLog'.
* build-aux/gitlog-to-changelog: New file, from Gnulib.
* build-aux/gitlog-to-emacslog: New file.
* CONTRIBUTE: Document the revised workflow.
* Makefile.in (clean): Remove *.tmp and etc/*.tmp*
instead of just special cases.
(CHANGELOG_HISTORY_INDEX_MAX, CHANGELOG_N, gen_origin): New vars.
(ChangeLog, unchanged-history-files, change-history)
(change-history-commit): New rules.
* admin/admin.el (make-manuals-dist--1):
Don't worry about doc/ChangeLog.
* admin/authors.el: Add a FIXME.
* admin/make-tarball.txt:
* lisp/calendar/icalendar.el:
* lisp/gnus/deuglify.el:
* lisp/obsolete/gulp.el:
* lwlib/README:
Adjust to renamed ChangeLog history files.
* admin/merge-gnulib (GNULIB_MODULES): Add gitlog-to-changelog.
* admin/notes/repo: Call it 'master' a la Git, not 'trunk' a la Bzr.
Remove obsolete discussion of merging ChangeLog files.
New section "Maintaining ChangeLog history".
* build-aux/git-hooks/pre-commit:
Reject attempts to commit files named 'ChangeLog'.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* make-dist: Make and distribute top-level ChangeLog if there's a
.git directory. Distribute the new ChangeLog history files
instead of scattered ChangeLog files. Distribute the new files
gitlog-to-changelog and gitlog-to-emacslog.
Fixes: bug#19113
