[Bug libstdc++/87618] [9 Regression] Missing symbol for std::__cxx11::basic_stringbuf, std::allocator >::basic_stringbuf()

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87618

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes, I forgot to close it.