RFR: 7076487 (sctp) SCTP API classes does not exist in JDK for Mac

[Michael McMahon]

Can I get the following change for jdk 8 reviewed please?

It's a simple build change to enable compilation of the dummy
SCTP API layer on macosx, plus the dummy implementation
used on windows.

The existing jdk_sctp tests cover this.

http://cr.openjdk.java.net/~michaelm/7076487/webrev.1/

Thanks,
Michael.