Proposal for adding O_DIRECT support into JDK 9

[Brian Burkhalter]

Hi,

I updated version 18 of the patch with the fix for the compilation errors on macOS:

http://cr.openjdk.java.net/~bpb/8164900/webrev.18/

This ran successfully through our regression harness for the IO and NIO core tests and all platforms passed. I also re-reviewed the code changes once again.

Barring objections to the contrary, I am ready to sponsor this version.

Thanks,

Brian