[Bug c++/33255] A warning for "unused" typedefs?

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33255

--- Comment #20 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-07-24 22:54:05 UTC ---
... or maybe not, because actually _GLIBCXX_CONCEPT_CHECKS defines used
typedefs, only, pointless besides type checking.

We should also check -D_GLIBCXX_DEBUG. This one is serious.