[Bug libstdc++/81751] [5/6/7 Regression]__basic_file::sync() may flush _all_ files

[bugzilla.volker at kabelmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81751

--- Comment #9 from Volker Wehrs <bugzilla.volker at kabelmail dot de> ---
Thank you, I guess that change should fix the bug.