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

* doc/emacs/files.texi (Interlocking): Point user at detailed
file locking description in lisp reference manual.  Add index
entry for '.#' to improve disoverability of information about locking.

* doc/lispref/files.texi (File Locks): Describe in detail what
the form of the lock file is.  Add index entry for '.#' to
improve disoverability of information about locking.

* src/filelock.c (create-lockfiles): Add cross reference to
file locking in user manual and to 'lock-buffer'.  Add string
'.#' to help users find the doc string.

Run admin/update-copyright.

Most of this change is to boilerplate commentary such as license URLs.
This change was prompted by ftp://ftp.gnu.org's going-away party,
planned for November.  Change these FTP URLs to https://ftp.gnu.org
instead.  Make similar changes for URLs to other organizations moving
away from FTP.  Also, change HTTP to HTTPS for URLs to gnu.org and
fsf.org when this works, as this will further help defend against
man-in-the-middle attacks (for this part I omitted the MS-DOS and
MS-Windows sources and the test tarballs to keep the workload down).
HTTPS is not fully working to lists.gnu.org so I left those URLs alone
for now.

* lisp/files.el (make-temp-file): Let make-temp-file-internal do
the work of inserting the text.
* src/fileio.c (Fmake_temp_file_internal): New arg TEXT.
All callers changed.

This incorporates:
2017-08-15 renameat: ensure declaration in <stdio.h> on NetBSD
2017-08-15 extensions: enable NetBSD specific extensions
2017-08-14 open: support O_CLOEXEC
2017-08-13 reallocarray: new module
* admin/merge-gnulib (AVOIDED_MODULES): Remove ‘open’, since
it now supports O_CLOEXEC and this simplifies Emacs.
* build-aux/config.guess, lib/fcntl.in.h, lib/stdio.in.h:
* lib/stdlib.in.h, m4/extensions.m4, m4/stdlib_h.m4:
Copy from Gnulib.
* lib/cloexec.c, lib/cloexec.h, lib/open.c:
* m4/mode_t.m4, m4/open-cloexec.m4, m4/open.m4:
New files, copied from Gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib-src/etags.c (O_CLOEXEC) [WINDOWSNT]:
Remove, as Gnulib does this for us.
* src/filelock.c (create_lock_file):
* src/sysdep.c (emacs_open, emacs_pipe):
Don’t worry about O_CLOEXEC == 0, as Gnulib no longer sets it to 0.

For the motivation behind this patch, please see Bug#28023 and:
http://emacshorrors.com/posts/make-temp-name.html
Although, given the recent changes to Tramp, the related security
problem in make-temp-file is already fixed, make-temp-file still has
several unnecessary system calls.  In the typical case on GNU/Linux,
this patch replaces 8 syscalls (symlink, open, close, readlinkat, uname,
getpid, unlink, umask) by 2 (open, close).
* admin/merge-gnulib (GNULIB_MODULES): Add tempname, now
that Emacs is using it directly.
* configure.ac (AUTO_DEPEND): Remove AC_SYS_LONG_FILE_NAMES;
no longer needed.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lisp/files.el (files--make-magic-temp-file): Rename from
make-temp-file.
(make-temp-file): Use make-temp-file-internal for
non-magic file names.
* src/fileio.c: Include tempname.h.
(make_temp_name_tbl, make_temp_name_count)
(make_temp_name_count_initialized_p, make_temp_name): Remove.
(Fmake_temp_file_internal): New function.
(Fmake_temp_name): Use it.
* src/filelock.c (get_boot_time): Use Fmake_temp_file_internal
instead of make_temp_name.

* src/fileio.c (Frename_file): Avoid calling Ffile_directory_p
more than once on FILE.  Use renameat_noreplace, so that we can
ask the user (and unlink and retry) only if this fails with errno
== EEXIST or ENOSYS.  This avoids the need to ask the user for
permission to do an operation that will fail anyway.  Simplify
computation of ok_if_already_exists for subsidiary functions.
* src/filelock.c (rename_lock_file): Prefer renameat_noreplace
if it works, as this avoids the need to link and unlink.
* src/lisp.h (renameat_noreplace): New decl.
* src/sysdep.c [HAVE_LINUX_FS_H]: Include linux/fs.h and sys/syscall.h.
(renameat_noreplace): New function.