Implement partial LLVM 3.3+ compatibility fixes. Aim is successful compi...

...lation from source only, binary is not verified; use at your own risk.

Remaining issues in Executor.cpp:
  llvm::sys::Process
    GetTotalMemoryUsage() dropped in r171327
  llvm::Module
    Support for dependent libraries dropped in r168694
  llvm::Attributes
    Rewritten to implement Attribute, AttributeSet, and AttrBuilder, beginning with r165917 (see http://llvm.org/docs/HowToUseAttributes.html)
  llvm::APFloat
    APFloat constructor requires explicit semantics from r173138