pki: Fix build warning about unused variables.
cmake: Check for libutil.h on FreeBSD.
examples: Add missing include on FreeBSD.
config: Add missing HAVE_LIBUTIL_H define in config.h

Signed-off-by: Audrius Butkevicius <audrius.butkevicius@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
examples: Add ssh_server_fork example

Signed-off-by: Audrius Butkevicius <audrius.butkevicius@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
examples: Remove old samplesshd.
examples: Remove old samplesshd-tty.
cmake: Merge server examples.
examples: Add missing include for stderr.

This should fix the build on FreeBSD.