Fix OSX CMake build

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@217667 91177308-0d34-0410-b5e6-96231b3b80d8
Fix lldb-mi driver for running on OSX.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@217668 91177308-0d34-0410-b5e6-96231b3b80d8