[8u40] review request: RT-34388: [Mac] Update build system to properly support Xcode 5 and later

[Kevin Rushforth]

Dave D and Dave H,

Please review the following:

https://javafx-jira.kenai.com/browse/RT-34388
http://cr.openjdk.java.net/~kcr/RT-34388/webrev.00/

Thanks.

-- Kevin