Add support for lazily linking bitcode files (using a new
-mlink-bitcode-file flag), and more generally llvm::Modules, before
running optimisations.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143314 91177308-0d34-0410-b5e6-96231b3b80d8
11 files changed