[llvm] [llvm-objcopy] Add llvm-objcopy option --set-visibility-sym (PR #80872)

[James Henderson via llvm-commits]

https://github.com/jh7370 requested changes to this pull request.

Thanks for the patch! The new option seems reasonable to me, but could you outline what the motivation is for you to have this option? You could after all remove a symbol and readd it with the new visibility as a workaround.

Have you looked at whether GNU objcopy supports this sort of option? If they do, it's important that the option name matches. If they don't, I think the option name should be `--set-symbol-visibility` which would line up better with the `--new-symbol-visibility` option name apart from anything else.

Finally, please update the llvm-objcopy documentation at llvm/docs/CommandGuide/llvm-objcopy.rst to describe the new option.

https://github.com/llvm/llvm-project/pull/80872