-@item
-The glibc extension of using @samp{W;} in the optstring argument to
-allow @code{-W foo} to behave synonymously with @code{--foo} is not
-very reliable, even in glibc.
-@item
-Mixing a leading @samp{-} or @samp{+} with a leading @samp{:} in the
-optstring argument has inconsistent effects across platforms.