gallivm: Fix build for LLVM 3.2

Do not rely on LLVMMCJITMemoryManagerRef being available.
The c binding to the memory manager objects only appeared
on llvm-3.4.
The change is based on an initial patch of Brian Paul.

Reviewed-by: Brian Paul <brianp@vmware.com>
Tested-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Signed-off-by: Mathias Froehlich <Mathias.Froehlich@web.de>
4 files changed