Code review request: 7186778 MachO decoder implementation for MacOSX

[Zhengyu Gu]

This is the implementation of MachO decoder for MacOSX. The 
implementation is based on the patch provided by Kevin Walls, I modified 
it to fit it into current decoder framework.


CR: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7186778
Webrev: http://cr.openjdk.java.net/~zgu/7186778/webrev.00/

Tests:
   The repo has ran through JPRT. I also used NMT queries to display the 
decoded callsites.


Thanks,

-Zhengyu