instance, @option{-Wno-syntax} will hide the warnings about unused
variables.
-The categories output by default are @samp{syntax} and
+The categories output by default are @samp{obsolete}, @samp{syntax} and
@samp{unsupported}. Additionally, @samp{gnu} and @samp{portability}
are enabled in @option{--gnu} and @option{--gnits} strictness.