part of an asm .symver directive as being used. This prevents referenced
functions from being internalized and deleted.
Without the patch to LTOModule.cpp, the test case will produce the error:
LLVM ERROR: A @@ version cannot be undefined.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205221 91177308-0d34-0410-b5e6-96231b3b80d8
