Add wip/libbsd to wip/Makefile
Import libbsd-0.4.2 as wip/libbsd.

This library provides useful functions commonly found on BSD systems,
and lacking on others like GNU systems, thus making it easier to port
projects with strong BSD origins, without needing to embed the same code
over and over again on each project.

Currently only known to work on Linux, I suspect other glibc based systems would
work too.
update wip/cpdup to version 1.17

On systems where it is available, use wip/libbsd; on systems that
neither have the required BSD MD5 functions natively nor support libbsd
(i.e. Darwin), leave out MD5 support.

Change maintainer to me, as suggested by Adam Hoka.
wip/libbsd/buildlink3.mk: do not construct an empty buildlink3 node

fix for a bug introduced by trying to silence a pkglint warning. This
buildlink3.mk is rigged to be a NOOP on platforms where libbsd won't
build (as per Makefile.common) - the buildlink tree statements must be
within this .if/.endif block