The NetBSD implementations have different prototypes to the ones coming
from OpenBSD, which will break builds, and have caused segfaults at
run-time. We provide now both interfaces with different prototypes as
different version nodes allow selecting them at compile-time, defaulting
for now to the OpenBSD one to avoid build-time breakage, while emitting
a compile-time warning. Later on, in 0.10.0, we will be switching the
compile-time default to the NetBSD version.

Ref: http://gnats.netbsd.org/44977
Fixes: https://bugs.debian.org/899282