kern/52657: current time does not advance on NetBSD sparc64

[bruno%clisp.org@localhost]

>Number:         52657
>Category:       kern
>Synopsis:       current time does not advance on NetBSD sparc64
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Oct 25 20:25:00 +0000 2017
>Originator:     Bruno Haible
>Release:        8.0_BETA
>Organization:
GNU
>Environment:
NetBSD sparin.bruno.haible.de 8.0_BETA NetBSD 8.0_BETA (GENERIC.201709170600Z) sparc64

>Description:
A C program that calls sleep(1) never terminates.
The cause it that indeed the current time does not seem to advance:

sparin$ date
Wed Oct 25 20:37:20 CEST 2017
sparin$ date
Wed Oct 25 20:37:19 CEST 2017
sparin$ date
Wed Oct 25 20:37:20 CEST 2017
sparin$ date
Wed Oct 25 20:37:20 CEST 2017
sparin$ date
Wed Oct 25 20:37:20 CEST 2017

$ uptime
 8:37PM  up 7 mins, 1 user, load averages: 0.92, 0.51, 0.27

The machine is running for 1.5 hours.
It's emulated in qemu-system-sparc64 (qemu 2.10.0), which for fine for Linux guests.

Also, after logging out, I don't get a new login prompt (probably because that is triggered by a timer as well).
>How-To-Repeat:

>Fix: