[Bug c++/58201] [4.9 Regression] Undefined reference to `B::B(void const**)'

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58201

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> ---
In practice, this would block the release of 4.9.0. Thus hope for sure, it's
only matter of when.