Please rebase bundled LLVM to 3.4

[lucab]

LLVM 3.4 has just been released. It would be good to partially realign and rebase our patches on the 3.4 tag (before tagging 0.9?).

[lucab]

cc @luqmana who is the current submodule owner.

[alexcrichton]

I'm not sure if there's much for us to do on this front, the version of LLVM that we're using is tagged as 3.5-svn, (last committed to by LLVM on 12/27/12), so we're not terribly behind the current release. Updating LLVM is still a bit of a pain now, and there's still no ability to use a system LLVM (because still have non-upstreamed patches), so I would be surprised if this happened before 0.9.

[alexcrichton]

We've rebased LLVM to master recently (#11853)