Update config.guess and config.sub

Copy in the latest config.guess and config.sub from upstream git
master as of 2013-07-26 (revision 79c4c50fc754d742286706b4db5ed8ce2a0de925).
Our previous version didn't recognize arm64.

Reported as Debian bug 717840.

ticket: 7683 (new)
tags: pullup
target_version: 1.11.4