http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51785
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-02-05 21:26:26 UTC --- Though personally I'm not concerned if libstdc++ doesn't define gets(), noone should be using it, I am concerned that libstdc++ fails to build because of the using decl.