time: Support Irix 6 location for zoneinfo files.
time: Support Irix 6 location for zoneinfo files.

R=rsc
CC=golang-dev
http://codereview.appspot.com/4440066
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go