RFR: JDK-8205424: Change to Xcode 9.4 for building on Macosx at Oracle

[Phil Race]

Looks fine.

-phil.

On 06/20/2018 09:07 AM, Erik Joelsson wrote:
> It's time for Oracle to change the official compiler used for building 
> OpenJDK on Macosx. The new version will be 9.4 and the build will 
> happen on Macosx 10.13(.4).
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8205424
>
> Webrev: http://cr.openjdk.java.net/~erikj/8205424/webrev.01/
>
> /Erik
>