Comment 7 for bug 305176

ok, lets assume that you meant with "can not be ignored" actually "must not be ignored". now thats where the definitions in RFC2119 kick in:

2. MUST NOT This phrase, or the phrase "SHALL NOT", mean that the
   definition is an absolute prohibition of the specification.

4. SHOULD NOT This phrase, or the phrase "NOT RECOMMENDED" mean that
   there may exist valid reasons in particular circumstances when the
   particular behavior is acceptable or even useful, but the full
   implications should be understood and the case carefully weighed
   before implementing any behavior described with this label.

The documentation correctly states SHOULD NOT, and thats distinctively different from MUST NOT.

I already agreed that glibc is over the top, nevertheless the (void)ify trick doesn't suppress the warning, and either that behaviour is a bug or the behaviour that assigning to a dummy variable (which is never read and therefore dead storage) doesn't warn is a bug. you choose.