Comment 1 for bug 1056633

-Wextra procudes a lot of useful warnings, as I found out when I turned it on and filtered out the unused parameter warnings (see bug #1032313).

In addition, I want to know when I'm not using a parameter so I can make a conscious decision about whether I just made a mistake or whether I indeed don't need the parameter. If so, it is trivial to remove the warning by commenting out the identifier. (I normally leave the identifier in place for documentation, rather than deleting it.)