Don't look for umem on FreeBSD, which have dummy stub version for
dtrace or ZFS compatibility.

Generally restrict probes for Solaris specific stuff to when we
run on solaris, no need to make configure slower than it is.

Don't pretend we can get anywhere without poll(2) we use it for
lots of things:  Remove #if conditionals around poll-acceptor.

Sort a couple of lists, before they get too unsorted.

Submitted by:	Theo Schlossnagle



git-svn-id: http://www.varnish-cache.org/svn/trunk@3113 d4fa192b-c00b-0410-8231-f00ffab90ce4