(1) Code to generate pthread create, join, exit calls

(2) Have to generate code for a new Launch function which can be called by
pthread_create and which extracts the root inputs from a memory location i8*.
(3) Formatted the different files to be more consisitent with LLVM coding
principles
M    llvm/include/llvm/BuildDFG/BuildDFG.h
M    llvm/include/llvm/IR/DFGraph.h
M    llvm/lib/Transforms/BuildDFG/BuildDFG.cpp
M    llvm/lib/Transforms/DFG2LLVM_X86/DFG2LLVM_X86.cpp