[Bug libstdc++/66145] [5/6/7 Regression] std::ios_base::failure objects thrown from libstdc++.so use old ABI

[boris at kolpackov dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145

--- Comment #26 from Boris Kolpackov <boris at kolpackov dot net> ---
> If breaking the old ABI was an option we wouldn't be in this situation in the first place.

By throwing the new version you are breaking the ABI. The point I was trying to
make is that maybe in this case we can allow the old code to still limp along
(and thus make this change more palatable).