PR libstdc++/9533

[Pétur Runólfsson]

> >It seems that O_NONBLOCK is still being used in 
> basic_file_stdio.cc on
> >the 3.3 branch. Can this please be fixed before 3.3 is released?
> >
> >I think it would be acceptable to just revert the fix for 
> libstdc++/6746
> >if the patch for 3.4 is considered too invasive.
> >
> Seems really too late for 3.3.0.

I believe high priority regressions may still be fixed.

I don't think it is acceptable to release 3.3 with fstream essentially
unusable.

Petur