Re: boot-time: straighten code

[Bruno Haible <bruno@clisp.org>]

Paul Eggert wrote:
> I installed the attached patch into Emacs 
> master, which you should be able to test via:
> 
> 	git clone https://git.savannah.gnu.org/git/emacs.git
> 	cd emacs
> 	./autogen.sh
> 	./configure
> 	make
> 	src/emacs
> 
> Please give it a try, especially on any MS-Windows platform you happen 
> to have. I have tested only on Ubuntu 23.04 so far.
> 
> A simple way to test is to use Emacs to start editing a file (without 
> saving) and then inspect the symbolic link .#* that Emacs uses as a lock 
> file. The trailing digits of that link's contents should be the boot 
> time. These symlinks are Emacs's only use of boot time.

Here are my test results. On each of the following platforms, after
regenerating the current 'configure' file and then building the 'emacs'
directory from today, with the configure options
  --disable-silent-rules --without-all --without-x
then running "./emacs $HOME/hello.c", editing that buffer, opening
a 'M-x shell' buffer, and looking at the $HOME/.#hello.c symlink,
I can see that its last component is exactly the time_t value of the
boot time, as displayed by the gnulib 'test-readutmp' test. So, the
test passes on all these platforms:
  - Linux: Ubuntu 22.04, Alpine Linux
  - Debian GNU/Hurd 2022
  - Debian GNU/kFreeBSD 7
  - NetBSD 9.3
  - OpenBSD 7.2
  - Cygwin 2.9.0

I could not test the Windows binaries from corwin, due to problems mentioned in
<https://lists.gnu.org/archive/html/emacs-devel/2023-08/msg00543.html>.

Also, I could not test on Android (in Termux), due to a build failure, cf.
<https://github.com/termux/termux-packages/issues/6592>.

Bruno