Re-enable compact unwind use on Mac platforms.
When lldb has a binary with protected section contents,
don't use the on-disk representation of that compact 
uwnind -- read it only out of live memory where it has
been decrypted.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@224670 91177308-0d34-0410-b5e6-96231b3b80d8