http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57119
--- Comment #11 from Dongsheng Song <dongsheng.song at gmail dot com> 2013-04-30 11:43:42 UTC --- Please see gcc/config-v2.log and i686-w64-mingw32/libstdc++-v3/config-v2.log, still not build libstdc++-6.dll