Problem: In Ruby we can define a nested module/class the safe
way (in the sense, if the parent module does not exist, it will
define it:

  module M
    module N
    end
  end

If M already exists, we can also write:

  module M::N; end

With the later notation, the tag generated by etags will be M::N.
When browsing the code, using xref-find-definitions when the point
is on N, will not be able to find the definition of N because the
implicit tag name is M::N.

This is the same problem with nested classes or even some rare
allowed definitions like explicitely defining a module/class from
the global namespace:

  class ::A; end

Solution: We need to give an explicit tag name.  To achieve this,
on module/class definition we truncate the name to the last found
column.
* lib-src/etags.c (Ruby_functions): Support "::" in module
definitions.
* test/manual/etags/README: Update instructions.
* test/manual/etags/ruby-src/test1.ru: Add identifiers with "::".
* test/manual/etags/CTAGS.good:
* test/manual/etags/CTAGS.good_crlf:
* test/manual/etags/CTAGS.good_update:
* test/manual/etags/ETAGS.good_1:
* test/manual/etags/ETAGS.good_2:
* test/manual/etags/ETAGS.good_3:
* test/manual/etags/ETAGS.good_4:
* test/manual/etags/ETAGS.good_5:
* test/manual/etags/ETAGS.good_6:
* test/manual/etags/ETAGS.good_7: Adapt expected results to the
change.  (Bug#77421)

Copyright-paperwork-exempt: yes

Remove our old ctags and suggest Universal Ctags instead.
This fixes a FIXME in lib-src/Makefile.in and speeds up compilation
quite a bit on my older CPU when I compile with	--enable-gcc-warnings.
It also lessens installation and runtime footprint. (Bug#76322)
* .gitignore: Remove lib-src/ctags.
* admin/authors.el (authors-renamed-files-alist): Remove ctags.1.
* admin/check-man-pages: ctags.1 is no longer a special case.
* admin/quick-install-emacs (PUBLIC_LIBSRC_BINARIES): Remove ctags.
* cross/Makefile.in (LIBSRC_BINARIES): Remove lib-src/ctags.
* doc/man/ctags.1, lib-src/ctags.c: Remove.
* java/Makefile.in (CROSS_LIBSRC_BINS): Remove ctags.
* lib-src/Makefile.in (INSTALLABLES): Remove ctags${EXEEXT}.
(ctags${EXEEXT}): Remove.
* lib-src/etags.c (CTAGS): Remove.  All uses replaced by ...
(ctags): ... this new static var.
(STDIN): Remove macro.  All uses replaced by new STDIN_OPTION constant.
(CTAGS_OPTION, STDIN_OPTION): New contants.
(longopts): New --ctags option.
(ctags_default_C_help): New constant,
to override default_C_help at runtime.
(default_C_help): Now always the etags version.
(C_LANG_NAMES_INDEX): New macro.
(print_language_names): Do not assume etags.
(PROGRAM_NAME): Remove.  All uses removed.
(print_help): Document --ctags if PRINT_UNDOCUMENTED_OPTIONS_HELP.
(main): Support new --ctags option, and support all [ce]tags options.
* test/manual/etags/Makefile (CTAGS_PROG):
Now etags --ctags, since there is no longer a ctags.

* configure.ac (libgccjit_not_found_err)
(libgccjit_dev_not_found_err):
* doc/emacs/buffers.texi (List Buffers):
* doc/lispref/elisp.texi (Tree-sitter C API):
* doc/lispref/functions.texi (What Is a Function):
* doc/lispref/parsing.texi (Parsing Program Source)
(Tree-sitter C API):
* doc/misc/gnus.texi (The Gnus Registry):
* etc/DEBUG:
* etc/NEWS:
* etc/NEWS.25:
* etc/NEWS.26:
* etc/NEWS.28:
* etc/NEWS.30:
* etc/TODO:
* lib-src/emacsclient.c (print_help_and_exit):
* lisp/auth-source.el (auth-source-search):
* lisp/cedet/semantic/bovine/el.el (emacs-lisp-mode):
* lisp/cedet/semantic/wisent/comp.el
(wisent-automaton-lisp-form):
* lisp/cedet/srecode/el.el (srecode-semantic-apply-tag-to-dict):
* lisp/editorconfig.el
(editorconfig-get-local-variables-functions):
* lisp/emacs-lisp/bindat.el (bindat-type):
* lisp/emacs-lisp/byte-opt.el (byte-compile-inline-expand):
* lisp/emacs-lisp/cconv.el (cconv-make-interpreted-closure):
* lisp/emacs-lisp/cl-macs.el (cl--labels-convert):
* lisp/emacs-lisp/lisp-mode.el (lisp-fdefs)
(lisp-fill-paragraphs-as-doc-string):
* lisp/emacs-lisp/macroexp.el (macroexp--fgrep):
* lisp/emacs-lisp/oclosure.el (cconv--interactive-helper):
* lisp/emacs-lisp/re-builder.el:
* lisp/erc/erc-button.el (erc-emacswiki-lisp-url):
* lisp/help-fns.el
(help-fns--describe-function-or-command-prompt):
* lisp/menu-bar.el (menu-bar-search-documentation-menu):
* lisp/net/tramp-message.el (tramp-debug-font-lock-keywords):
* lisp/org/org-capture.el (org-capture):
* lisp/org/org.el (org-category, org-todo):
* lisp/org/ox.el (org-export-async-start):
* lisp/progmodes/elisp-mode.el (emacs-lisp-mode):
* lisp/progmodes/peg.el (peg-translate-exp):
* lisp/progmodes/ruby-ts-mode.el:
* lisp/woman.el (woman-mode, woman-parse-numeric-arg):
* src/chartab.c (map_char_table_for_charset):
* src/fns.c (extract_data_from_object):
* src/frame.c (do_switch_frame):
* src/keyboard.c (make_lispy_event):
* test/lisp/emacs-lisp/cl-macs-tests.el (cl-&key-arguments):
* test/lisp/emacs-lisp/shortdoc-tests.el
(shortdoc-help-fns-examples-function-test):
* test/manual/etags/c-src/emacs/src/keyboard.c
(make_lispy_event): Fix capitalization ELisp -> Elisp.

This file is new with the portable dumper.

These are dates that admin/update-copyright did not update.

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

* lib-src/etags.c (regex_tag_multiline): Fix off-by-one error in
determining the end of the tag matched by a multiline regexp.
(Bug#73771)

* test/manual/etags/ETAGS.good_4:
* test/manual/etags/ETAGS.good_5:
* test/manual/etags/ETAGS.good_6: Adjust test results to the above
change.

This adds '--no-fallback-lang' and '--no-empty-file-entries'
options, and their opposites '--fallback-lang' and
'--empty-file-entries'.
* lib-src/etags.c (fallback_lang, empty_files): New toggles.
(main): Initialize them to 'true'.
(longopts) [!CTAGS]: Add the '--(no-)fallback-lang' and
'--(no-)empty-file-entries' options.
(find_entries): If 'fallback_lang' is false, don't attempt Fortran
and C/C++ fallbacks.
(print_help): Add help for new options.
(main): If 'empty_files' is false, don't output file entries for
files that have no tags.  (Bug#73484)

* doc/emacs/maintaining.texi (Create Tags Table):
* etc/NEWS:
* doc/man/etags.1: Document the new options.

* test/manual/etags/Makefile (check): Add test for new options.
* test/manual/etags/ETAGS.good_7: New file.

This fixes some unlikely bugs and removes the temptation
of using ctype.h.  Although some uses were correct,
many weren't.
* lib-src/ebrowse.c: Include c-ctype.h, not ctype.h.
* lib-src/emacsclient.c: Include c-ctype.h, not ctype.h.
* lib-src/update-game-score.c: Include c-ctype.h, not ctype.h.
All uses changed.