[Bug libstdc++/77582] Improve std::string::clear performace

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77582

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patches goto gcc-patches@ and libstdc++@.  Note !_GLIBCXX_USE_CXX11_ABI is most
likely not going to be used for 90% of applications.  It is only needed if you
are linking between old binaries and using the new compiler.