how to deal with variable set but not used warnings?

mmacy has sent me a bunch of warnings of the "variable set but not used" kind
generated by gcc8.

When I've looked at the code, these are for RPC arguments I parse but do not
use at this time.
I'd  like to leave the code in place, since these arguments may be needed in the
future and it is hard to figure out how to get them years from now, when they
might be needed.
I can think of 3 ways to handle this:
1 - Get rid of the code. (As above, I'd rather not do this.)
2 - Wrap the code with "#if 0"/"#endif" or similar. I'll admit that I find this rather
      ugly and tends to make the code harder to follow.
3 - Leave the code and add a comment w.r.t. why the variables are set but not used.

So, what do others think is the preferable alternative?
(Or maybe you have a #4 that seems better than any of these.)

Thanks for your comments, rick