X86: correct library call setup for Windows itanium

This target is identical to the Windows MSVC (and follows Microsoft ABI for C).
Correct the library call setup for this target.  The same set of library calls
are missing on this environment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213883 91177308-0d34-0410-b5e6-96231b3b80d8