Remov­ing super­flous calls to basename/dirname in bsd.port.mk

I just sub­mit­ted my patch to remove calls (exec()ing) to basename/dirname in bsd.port.mk to GNATS. I did­n’t time if this improves any­thing, but I assume doing a regex replace­ment in a make-variable uses less resources than doing a fork()&exec() or a sys­tem() call.

I don’t think this gives a huge improve­ment at all, it’s maybe even below the mea­sure­ment thresh­old, but hey, why using exter­nal tools if the inter­nal fea­tures are enough to do what you want? At least this patch is record­ed now somewhere…