[PATCH] [lld] [mach-o] implement minimal __unwind_info support

[Tim Northover]

Thanks for the reviews. I've committed it as r218703 and r218704 (I ran clang-format for the first one, but forgot the file-level comment).

I'll work on filling in the gaps now that the basic pass is in place.

Cheers.

Tim.

http://reviews.llvm.org/D5261