[For those cc'ed, the thread's at <https://bugs.gnu.org/64937#142>.]

On 2023-08-09 07:29, Bruno Haible wrote:

> And on Alpine Linux, while /var/run/utmp is empty, its time stamp is
> essentially the boot time.
> 
> The approach used by Emacs, namely to look at the time stamp of
> /var/run/random-seed, is therefore essentially one of the best approaches.
> It just needs to also look at /var/lib/systemd/random-seed and - on Alpine
> Linux - /var/run/utmp .

Thanks for looking into this. Clearly Emacs had some catching up to do, 
since it was using a location for the random-seed file that current 
GNU/Linux distros no longer use. To try to fix this I installed the 
attached patch to Emacs master on Savannah.

This patch does not address the problem for Alpine, nor I suspect for 
Android. I suppose Alpine could use the timestamp of /var/run/utmp (or 
is that /run/utmp?) but I don't know how 'configure' would reliably 
detect it's being built or cross-built for Alpine. I'll cc this to 
Natanael Copa, who does the Alpine ports for Emacs, to see whether he 
can give advice.

Also, I don't know how Android records boot time so I'll cc this to Po 
Lu, the main developer for Emacs on Android.