Bug#631639: __unused in libbsd. workaround for #522773 (linux) and #522774 (libc)

[Guillem Jover <guillem@debian.org>]

On Sat, 2011-06-25 at 17:24:00 +0000, Thorsten Glaser wrote:
> That won’t help. The overlay mode uses pkg-config which no BSD thing
> touches.

Well, even OpenBSD has its own re-implementation:

  <http://www.openbsd.org/cgi-bin/man.cgi?query=pkg-config&sektion=1&format=html>

regards,
guillem