[9] RFR of 8074821: Resolve disabled warnings for libnio

[Brian Burkhalter]

Please review at your convenience.

Issue:	https://bugs.openjdk.java.net/browse/JDK-8074821
Patch:	http://cr.openjdk.java.net/~bpb/8074821/webrev.00/

Summary: Enable the indicated warnings and correct the code which provoked them.

On Windows I still saw two places in Net.c provoking warning C4996 about GetVersionEx() (lines 95 and 109 in the new version) being deprecated, but I don’t think we can replace this functionality with IsWindowsVistaOrGreater() with the version of the MS compiler we are using. If I am incorrect on this point please let me know.

Thanks,

Brian