[PATCH] MCJIT MachO debugging support

[Lang Hames]

LGTM too.

There's a serious caveat attached to this, which is that I think the idea of re-writing object files in-place is fundamentally broken. This will probably work for MCJIT because it emits its object files directly into memory. For RuntimeDyld, which may memmap its object files, this almost certainly won't work. We should aim to have a nicer interface between the JIT and the debugger. This patch doesn't make things any worse than they already were though, so I don't want to hold it up.

Thanks again for working on this Keno!

http://reviews.llvm.org/D4005