port-amd64/56039: abort on dhcpd for 9.99.80

[nervoso%k1.com.br@localhost]

>Number:         56039
>Category:       port-amd64
>Synopsis:       abort on dhcpd for 9.99.80
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Mar 04 22:40:00 +0000 2021
>Originator:     sergio lenzi
>Release:        NetBSD 9.99.80
>Organization:
k1 sistemas
>Environment:
NetBSD server500.csabino 9.99.80 NetBSD 9.99.80 (LZT64HEAD) #0: Mon Mar  1 17:31:31 -03 2021  NetBSD@server500.sabino:/home/NetBSD/BUILD/HEAD/amd64/OBJ/sys/arch/amd64/compile/GENERIC amd64
>Description:
a fresh build of NetBSD from sources on amd64, and probably on i386 too  result in core dump and message from dhcpd.. make the system unable to offer dhcp on the network

This problem does not happen in the 9.99.75 I tested
>How-To-Repeat:
build the system using fresh tarballs from http://nycdn.netbsd.org/pub/NetBSD-daily/HEAD/latest/source/sets

install system run system

supose your network is re0....

dhcpd -f re0  results....
===================================================================
Internet Systems Consortium DHCP Server 4.4.2
Copyright 2004-2020 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Config file: /etc/dhcpd.conf
Database file: /var/db/dhcpd.leases
PID file: /var/run/dhcpd.pid
Wrote 11 leases to leases file.
Listening on BPF/wm1/04:7d:7b:61:9a:8b/192.168.31.0/24
Sending on   BPF/wm1/04:7d:7b:61:9a:8b/192.168.31.0/24
Sending on   Socket/fallback/fallback-net
Server starting service.
/home/NetBSD/BUILD/HEAD/usr/src/external/mpl/bind/lib/libisc/../../dist/lib/isc/unix/socket.c:3305: fatal error: RUNTIME_CHECK(((__libc_mutex_unlock(((&sock->lock))) == 0) ? 0 : 34) == 0) failed
Abort trap (core dump)

>Fix:

A workaround was use isc-dhcpd from pkgsrc  both have version 4.4.2