Update on some PRs I'm working on

[Paolo Carlini]

Pétur Runólfsson wrote:

>>- 9875 and 9178
>>These are both about deficiencies for encodings > 1. They are
>>not too difficult to fix, IMO. I have already the fixes for
>>9875, except the underflow bits (yesterday Pétur provided some
>>testcases which I asked).
>>    
>>
>The best fix for underflow() is probably to add
>
>if (gptr() < egptr())
>  return *gptr();
>
(this vaguely reminds me page 678 of Josuttis ;)

>at the top (of course using traits operators and handling uflow
>correctly). I think the seekoff can then be avoided.
>This code should work for all values of codecvt::encoding(),
>as well as for pipes and other things for which seekoff
>doesn't work.
>
Thanks Pétur for the suggestion. I will take into account when, in a few 
days I hope,
I will actually get to 9875 and 9178 in detail.

Paolo.