ping6: Disable definition of the old copyright variable

[jansucan]

Summary

Disable definition of the old copyright variable

This fixes warning that the variable is unused when compiled with GCC
8, env CROSS_TOOLCHAIN=riscv64-gcc TARGET=riscv TARGET_ARCH=riscv64,
and WARNS=6.

Submitted by: Ján Sučan <[e-mail]>
Sponsored by: Google, inc. (Google Summer of Code 2019)

[asomers]

This change doesn't seem right. Anything involving #if 0 reeks. But this is basically exactly the same thing as what r114433 did, and nobody's reverted that change yet. So I'll accept it as is.

Maybe @rgrimes would have a better idea for a permanent solution. The intent of these strings seems to have been to embed copyright info into every binary. But thanks to the static, compilers would of course remove it. If we removed static, then we might achieve the original intention of the code. But since it's been > 20 years and nobody's complained, I think it would be better to convert all of these into comments.

[rgrimes]

My position is that "intent" in law carries a greater weight than "implementation". I agree that the intent of UCB was to embed the Copyright into the binary, and the fact that has been defeated by the choice of tools is on us to correct. Though Berne makes the binary copyright by default, it was still the intent of the original author to have these copyright strings appear. It is also very much understood in copyright law that "removing of any copyright" is an actionable item. Now, the likely hood that UCB would take action is moot. We could contact the UCB legal office and ask them for advice? Even a duplicate copyright can raise that question, I have seen no place an exception based on the fact that the same copyright appeared more than once.