[llvm] [Bazel] Support opt-driver library, like clang-driver (PR #79205)

[William Moses via llvm-commits]

wsmoses wrote:

I'm fine with that but FYI I emulated the clang approach, which does have this in Bazel (https://github.com/llvm/llvm-project/blob/03a61d34ebf4f8eeaa6861bec3ab39c75bb41778/utils/bazel/llvm-project-overlay/clang/BUILD.bazel#L2275) but not CMake (https://github.com/llvm/llvm-project/blob/03a61d34ebf4f8eeaa6861bec3ab39c75bb41778/clang/tools/driver/CMakeLists.txt#L26)

https://github.com/llvm/llvm-project/pull/79205