[RFC/patch] Fixing libstdc++/11378 and, while at it... ;)

[Paolo Carlini]

Benjamin Kosnik wrote:

>Eh. 
>
>I don't really like this patch. I'd prefer not to see special casing for
>unbuffered creep in again. And the bits that are there should be kept to
>a minimum. The problem is real, however, so at some point some kind of
>solution will have to go in: perhaps you could wait a bit on this one.
>
Ok, if you want so...

>Paolo, you mentioned you have other plans for this, that impact all (not
>just unbuffered sputn) calls. Perhaps you could do that first?
>
However, that work is much more dangerous than just fixing 11378 but 
affects the same virtual in a similar way: I considered fixing 11378 
sort of an exercise (for the first time having a non trivial 
filebuf::xsputn) in preparation for more complicate work.

Paolo.