ref: 0a101736b885578f673bc08b7fd040e977ede331
parent: d304dc8119a737c65eca8717e1f436a1e0edf880
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Thu Aug 7 17:11:11 EDT 2014
pc, pc64: make pc kaddr() check reject -KZERO address (thanks aiju)