Remove ctags program

Remove ctags program

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.

(cherry picked from commit 25d757535884da71ace29fd80b8b24dd3a8f9017)