[Bug libstdc++/91653] ostream::operator<<(streambuf*) should fail the ostream when write output stream error but not

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91653

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
GCC 4.9.2 has been unsupported for several years.