is actually an instrinsic that will not occur in libc. This list here
is not exhaustive but fixes the one places in test-suite where this occurs.
I have filed a bug against myself to research the full list and add them
to the array of such cases. In the future, actual stub generation will occur
in a later phase and we won't need this code because we will know at that time
during the compilation that in fact no helper function was even needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188149 91177308-0d34-0410-b5e6-96231b3b80d8
