Code review request: 8010192: Enable native JGSS provider on Mac

[Weijun Wang]

Please take a look at

    http://cr.openjdk.java.net/~weijun/8010192/webrev.00/

The Mac native JGSS provider is back. Besides reverting changes made in 
http://hg.openjdk.java.net/jdk8/tl/jdk/rev/5a2ab2c3f106, there are:

1. GSSManagerImpl.java: enable the provider
2. SunNativeProvider.java: library name from MIT added
3. Update gssapi.h, new lines copied from Mac's gssapi.h
4. Liberate a test.

Thanks
Max