Make it so. (This patch is in LowerCall_Darwin, which seems
to be used by SVR4 code as well; since that doesn't belong here,
I haven't worried about this case.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98077 91177308-0d34-0410-b5e6-96231b3b80d8