Make helpers static. Add missing include so LLVMInitializeObjCARCOpts gets C linkage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175264 91177308-0d34-0410-b5e6-96231b3b80d8
[asan] support long double on 64-bit. See https://code.google.com/p/address-sanitizer/issues/detail?id=151

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175266 91177308-0d34-0410-b5e6-96231b3b80d8