Const-correctness in libLTO

Looks like I was sloppy when bridging to C.
Thanks D. Blaikie for noticing!

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263885 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed