[llvm] [CMake] Check objcopy support for LLVM_SPLIT_DWARF (PR #80500)

[Mehdi Amini via llvm-commits]

joker-eph wrote:

So for all practical purpose, for Linux systems we support, you're saying that all the tools involved in the build will correctly support split dwarf out of the box, regardless of the combination compiler/linker that is enabled?

LGTM then.

https://github.com/llvm/llvm-project/pull/80500