PPC64 doesn't define SUPPORTS_NATIVE_CX8 ?

[David Holmes]

SUPPORTS_NATIVE_CX8 is used by platforms with full 64-bit CAS and 
atomics capability to elide the lock-based Unsafe jlong atomic update 
methods and avoid a runtime VM_Version::supports_cx8() check. I just 
noticed this isn't set for PPC64. Can I assume that is just an 
oversight? I have some changes to the lock-based code in the pipeline 
and can update the PPC64 code at the same time if desired.

Thanks,
David