build: Updates to enable AIX support

These are the core changes that allow AIX to compile.  There
are still some test failures as there are some patches needed for
libuv and npm that we'll need to contribute through those
communities but this set allows node to be built on AIX and
pass most of the core tests

The change in js2c is because AIX does not support $ in
identifier names.  See the discussion/agreement in
https://github.com/nodejs/node/issues/2272

PR-URL: https://github.com/nodejs/node/pull/2364


Reviewed-By: Ben Noordhuis <ben@strongloop.com>
Reviewed-By: Rod Vagg <r@va.gg>