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

[Fangrui Song via llvm-commits]

MaskRay wrote:

This change will cause trouble if a system does not provide `objcopy`. Clang -gsplit-dwarf doesn't need `objcopy`. I changed it a few years ago to use the internal ELF writer for non-Linux OSes.

GCC 8 is usually shipped with binutils 2.30+. See https://centos.pkgs.org/7/centos-sclo-rh-x86_64/devtoolset-8-binutils-2.30-47.el7.x86_64.rpm.html , far above than the `-gsplit-dwarf` requirement.

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