RFR: Add support for building on AArch64

[Robin Westberg]

Hi Nick,

> On 31 Oct 2019, at 12:01, Nick Gasson <Nick.Gasson at arm.com> wrote:
> 
> Hi,
> 
> What's the workflow for make changes to the PR? (the Mac build broke.) Should I amend the commit and force-push or add another commit to that branch?

Usually adding another commit is the preferred choice, this will enable automatic generation of incremental webrevs. But either works fine, when integrating the branch all commits will be squashed.

>>  Webrev: https://webrevs.openjdk.java.net/skara/231/webrev.00
> 
> This 404s for me - is that a known issue?

Sometimes it takes a little while to update I think, but usually it is quite fast. Looks like it is working now at least.

Best regards,
Robin

> 
> Thanks,
> Nick