[llvm] [DirectX] Add boilerplate integration of `objcopy` for `DXContainerObjectFile` (PR #153079)

[James Henderson via llvm-commits]

https://github.com/jh7370 commented:

Thanks for the updates. I've skimmed them briefly, but am going to need to give this another go over next week before I'm happy.

https://github.com/llvm/llvm-project/pull/153079