[v3] DR 282 and libstdc++/4402

[Benjamin Kosnik]

> But if you do not deal with the short-fixed case separately from the general fixed
> case and together with the non-fixed case, as you do in your final patch, there is no
> reason at all, IMO, to have __max_digits*4 for the non-fixed case, since that was a
> size dictated by the short-fixed case not by the non-fixed case by itself. For the
> common non-fixed case,  __max_digits*2, the current value, is perfectly ok, IMO.
> Perhaps __max_digits*3, just to be safe. Unbreakable, as you say.
> 
> So, what else can I add?

A tested patch to do the above, and adjust the comments is pre-approved.

Thanks,
benjamin