* lisp/format-spec.el: Use lexical-binding.  Remove dependence on
subr-x.el.
(format-spec-make): Clarify docstring.
(format-spec--parse-modifiers): Rename to...
(format-spec--parse-flags): ...this and simplify.  In particular,
don't bother parsing :space-pad which is redundant and unused.
(format-spec--pad): Remove, replacing with...
(format-spec--do-flags): ...this new helper function which performs
more of format-spec's supported text manipulation.
(format-spec): Autoload.  Allow optional argument to take on special
values 'ignore' and 'delete' for more control over what happens when
a replacement for a format specification isn't provided.  Bring back
proper support for a precision modifier similar to that of 'format'.

* lisp/battery.el (battery-format): Rewrite in terms of format-spec.
(battery-echo-area-format, battery-mode-line-format): Mention
support of format-spec syntax in docstrings.

* doc/lispref/strings.texi (Custom Format Strings):
* etc/NEWS: Document and announce these changes.

* lisp/dired-aux.el (dired-do-compress-to):
* lisp/erc/erc-match.el (erc-log-matches):
* lisp/erc/erc.el (erc-update-mode-line-buffer):
* lisp/gnus/gnus-sieve.el (gnus-sieve-update):
* lisp/gnus/gssapi.el (open-gssapi-stream):
* lisp/gnus/mail-source.el (mail-source-fetch-file)
(mail-source-fetch-directory, mail-source-fetch-pop)
(mail-source-fetch-imap):
* lisp/gnus/message.el (message-insert-formatted-citation-line):
* lisp/image-dired.el:
* lisp/net/eww.el:
* lisp/net/imap.el (imap-kerberos4-open, imap-gssapi-open)
(imap-shell-open):
* lisp/net/network-stream.el (network-stream-open-shell):
* lisp/obsolete/tls.el (open-tls-stream):
* lisp/textmodes/tex-mode.el:
Remove extraneous loads and autoloads of format-spec now that it is
autoloaded and simplify its uses where possible.

* test/lisp/battery-tests.el (battery-format): Test new format-spec
support.
* test/lisp/format-spec-tests.el (test-format-spec): Rename to...
(format-spec) ...this, extending test cases.
(test-format-unknown): Rename to...
(format-spec-unknown): ...this, extending test cases.
(test-format-modifiers): Rename to...
(format-spec-flags): ...this.
(format-spec-make, format-spec-parse-flags, format-spec-do-flags)
(format-spec-do-flags-truncate, format-spec-do-flags-pad)
(format-spec-do-flags-chop, format-spec-do-flags-case): New tests.

The metamail package was last released in 1994, and has been removed
from most GNU/Linux distributions due to being buggy and unmaintained.

* lisp/mail/metamail.el: Move from here...
* lisp/obsolete/metamail.el: ...to here.
* etc/NEWS: Mention its obsoletion.

This was missed in a previous commit to remove obsolete libraries.
Its deletion was already announced in NEWS.

* lisp/obsolete/levents.el: Delete file.  This library has been
obsolete since 23.2.

Emacs 23.2 was released 10 years ago.  old-whitespace.el has a
replacement in whitespace.el and is no longer relevant.  The other
libraries implement compatibility with Lucid Emacs, a modified version
of Emacs last released in the 1990s.

* lisp/obsolete/ledit.el:
* lisp/obsolete/lmenu.el:
* lisp/obsolete/lucid.el:
* lisp/obsolete/old-whitespace.el: Delete files.  These libraries have
been obsolete since Emacs 23.1 or 23.2.
* etc/NEWS: Announce their deletion.

* admin/authors.el (authors-ignored-files)
(authors-fixed-entries, authors-valid-file-names):
* lisp/emulation/viper.el (viper-mode):
* lisp/ffap.el (ffap-menu-ask): Remove references to deleted files.

05089a4d65 (origin/emacs-27) Tweak wording re constant variables
a1040861f1 Tweak setcar-related wording
751510f865 * lisp/image-mode.el: Add prefix key 's' and reduce depend...
9261a219ec * doc/emacs/windows.texi (Window Convenience): Decribe mor...
e1d42da0d6 Fix mutability glitches reported by Drew Adams
5805df74f5 Improve mutability doc
dca35b31d0 Improve mutability documentation
81e7d7f111 Document that quoting yields constants
5734339f40 * doc/lispref/keymaps.texi (Extended Menu Items, Easy Menu...
14a570afae Remove #' and function quoting from lambda forms in manual
d5ec18c66b * src/regex-emacs.c (re_match_2_internal): Rework comment ...
4df8a61117 Add new node "Image Mode" to Emacs Manual.
d7d5ee6c57 ; Fix a typo in cmdargs.texi (bug#40701)
5e9db48fbe * doc/lispref/display.texi (Customizing Bitmaps): Fix typo.
eebfb72c90 Document constant vs mutable objects better
6c187ed6b0 Improve documentation of 'sort-lines'
52288f4b66 Mention 'spam-stat-process-directory-age' in the documenta...
067b070598 ; Fix some typos and doc issues (bug#40695)

# Conflicts:
#	etc/NEWS

Suggested by Paul Eggert.

* lisp/files.el (directory-files-no-dot-files-regexp):
Clarify semantics and purpose.
* lisp/dired.el (dired-re-no-dot):
Define as obsolete alias of directory-files-no-dot-files-regexp.
(dired-delete-file):
* lisp/gnus/gnus-util.el (gnus-delete-directory):
* lisp/net/ange-ftp.el (ange-ftp-delete-directory):
* lisp/obsolete/vc-arch.el (vc-arch-trim-revlib):
* lisp/org/ob-core.el (org-babel-remove-temporary-directory):
* lisp/vc/vc-rcs.el (vc-rcs-unregister):
Use directory-files-no-dot-files-regexp.

a5f7c26907 (origin/emacs-27) * admin/authors.el: Add an author alias.
d87a4d1f4e Limit RLIMIT_NOFILE to FD_SETSIZE on macOS
e5ca8e5e73 Fix Elisp manual entry on 'set-window-configuration'
485f24223f ; Update ChangeLog.3
8f200254fb ; Update etc/AUTHORS
c7adc851ad * admin/authors.el: Add missing author aliases.
4acdd7fe58 Fix edge case errors in filename-matching regexps
5f36e21fe5 Clarify the doc string of 'yank'
13301d4266 New function erc-track-switch-buffer-other-window
38f7538d8f New function erc-switch-to-buffer-other-window

# Conflicts:
#	etc/NEWS

These changes fix actual or latent bugs in regexps that match
file names, such as PATTERN arguments to 'directory-files'.  See
https://lists.gnu.org/archive/html/emacs-devel/2020-04/msg00265.html

* admin/authors.el (authors-obsolete-files-regexps)
(authors-renamed-files-regexps):
* lisp/auth-source-pass.el (auth-source-pass-entries):
* lisp/calendar/todo-mode.el (todo-show, todo-find-filtered-items-file)
(todo-filter-items, todo-reset-nondiary-marker, todo-reset-done-string)
(todo-reset-comment-string, todo-reset-highlight-item):
* lisp/cedet/semantic/db-ebrowse.el (semanticdb-load-ebrowse-caches):
* lisp/cedet/semantic/texi.el (semantic-texi-associated-files):
* lisp/cedet/srecode/map.el (srecode-map-update-map):
* lisp/dired.el (dired-re-no-dot):
* lisp/emacs-lisp/autoload.el (update-directory-autoloads):
* lisp/emacs-lisp/shadow.el (load-path-shadows-find):
* lisp/files.el (auto-mode-alist, directory-files-no-dot-files-regexp):
* lisp/finder.el (finder-compile-keywords):
* lisp/generic-x.el (inetd-conf-generic-mode, named-boot-generic-mode)
(resolve-conf-generic-mode, etc-modules-conf-generic-mode):
* lisp/gnus/gnus-agent.el (gnus-agent-read-agentview)
(gnus-agent-regenerate-group, gnus-agent-update-files-total-fetched-for):
* lisp/gnus/gnus-cache.el (gnus-cache-articles-in-group):
* lisp/gnus/gnus-score.el (gnus-score-search-global-directories):
* lisp/gnus/gnus-util.el (gnus-delete-directory):
* lisp/gnus/gnus-uu.el (gnus-uu-dir-files):
* lisp/gnus/nndraft.el (nndraft-request-group):
* lisp/gnus/nnmh.el (nnmh-request-group, nnmh-request-create-group):
(nnmh-request-delete-group, nnmh-active-number, nnmh-update-gnus-unreads):
* lisp/gnus/nnspool.el (nnspool-request-group):
* lisp/gnus/spam-stat.el (spam-stat-process-directory)
(spam-stat-test-directory):
* lisp/help-fns.el (help-fns--first-release):
* lisp/help.el (view-emacs-news):
* lisp/international/quail.el (quail-update-leim-list-file):
* lisp/international/titdic-cnv.el (batch-titdic-convert):
* lisp/mail/mspools.el (mspools-set-vm-spool-files)
(mspools-get-spool-files):
* lisp/mail/rmail.el (rmail-secondary-file-regexp)
(rmail-speedbar-match-folder-regexp):
* lisp/net/ange-ftp.el (ange-ftp-delete-directory):
* lisp/net/tramp.el (tramp-use-absolute-autoload-file-names):
* lisp/obsolete/gulp.el (gulp-send-requests):
* lisp/obsolete/vc-arch.el (vc-arch-trim-revlib):
* lisp/org/ob-core.el (org-babel-remove-temporary-directory):
* lisp/progmodes/ebnf2ps.el (ebnf-file-suffix-regexp, ebnf-style-database):
* lisp/progmodes/executable.el (executable-command-find-posix-p):
* lisp/startup.el (command-line):
* lisp/textmodes/refer.el (refer-get-bib-files):
* lisp/url/url-about.el (url-probe-protocols):
* lisp/vc/vc-rcs.el (vc-rcs-register, vc-rcs-unregister):
* test/lisp/net/tramp-archive-tests.el
(tramp-archive-test19-directory-files-and-attributes):
* test/lisp/net/tramp-tests.el (tramp-test19-directory-files-and-attributes):
Replace ^ and $ with \` and \', respectively.
Use (rx (or (not ".") "...")), translated into "[^.]\\|\\.\\.\\.",
to match anything but "." and "..", instead of several incorrect
regexps.

See discussion at
https://lists.gnu.org/archive/html/emacs-devel/2020-01/msg00749.html .

* lisp/obsolete/iswitchb.el (iswitchb-summaries-to-end):
* test/src/regex-emacs-tests.el (regex-tests-BOOST-frob-escapes):
* test/lisp/help-fns-tests.el (help-fns-test-lisp-macro)
(help-fns-test-lisp-defun, help-fns-test-lisp-defsubst)
(help-fns-test-alias-to-defun, help-fns-test-bug23887):
Double backslashes for desired effect.
* lisp/org/ol.el (org-link-escape):
* lisp/net/nsm.el (nsm-protocol-check--rsa-kx)
(nsm-protocol-check--anon-kx, nsm-protocol-check--sha1-sig):
* lisp/obsolete/old-whitespace.el (whitespace-buffer):
* lisp/obsolete/rcompile.el (remote-compile-run-before):
* lisp/obsolete/vi.el (vi-end-of-blank-delimited-word):
* lisp/obsolete/vip.el (vip-current-major-mode)
(vip-paren-match, vip-switch-to-buffer)
(vip-switch-to-buffer-other-window, vip-kill-buffer)
(vip-get-ex-token, ex-edit):
* lisp/org/org-element.el (org-element--cache-sync-requests):
* lisp/org/org.el (org-sparse-tree):
* lisp/textmodes/reftex.el (reftex-report-bug):
* test/lisp/ibuffer-tests.el (ibuffer-save-filters):
* test/lisp/international/ucs-normalize-tests.el
(ucs-normalize-tests--insert-failing-lines):
* test/lisp/simple-tests.el (undo-test-kill-c-a-then-undo):
* test/lisp/textmodes/conf-mode-tests.el (conf-test-toml-mode):
* test/src/regex-emacs-tests.el (regex-tests-compare):
Remove redundant backslashes.