option -pthread in LDADD

[Roland Illig <roland.illig%gmx.de@localhost>]

Hi,

On https://releng.netbsd.org/cgi-bin/builds.cgi, the lint builds
currently fail since lint cannot handle the option -pthreads. This
option has been added in sbin/cgdconfig/Makefile on 2021-11-22.

Is it OK to add the option -pthreads to LDADD? If so, the 3 lint
commands in share/mk/bsd.*.mk probably need to be adjusted to filter out
-pthreads. Or maybe better, filter out anything but -llib and -Llibdir,
as this would allow me to occasionally add --coverage to LDADD for
testing purposes.

If it's not OK to add -pthreads to LDADD, where should it go instead?

Roland