build: first set of updates to enable PPC support

These are the core changes that allow pLinux BE/LE compile. They
don't include all of the changes needed for AIX which will follow
once we have pLinux up and running in the builds

PR-URL: https://github.com/nodejs/io.js/pull/2124


Reviewed-By: Ben Noordhuis <ben@strongloop.com>
Reviewed-By: Johan Bergstrom <bugs@bergstroem.nu>