[Patch] Fix istream::ignore + minor things

[Paolo Carlini]

Nathan Myers wrote:

>This means we must be careful not to overgeneralize results of testing. 
>  
>
Ok.

>Second, compiler core people seem very sensitive to whether a feature
>is actually used in the code they encounter (typically in bug reports)
>before they put any time into improving their implementation of that
>feature.  At the moment, they probably hardly ever see branch prediction 
>attributes, because its expression isn't portable.
>
Very, very interesting observation!

>Something else recommended by Geert Bosch (in 2004-05/msg01253.html)
>is to mark blocks that throw as no-return, because, as he says, "This 
>will cause GCC to automatically consider [entry] to it unlikely.  The 
>advantage is that you don't have to litter your source code at every 
>call site" -- or, presumably, the conditional expressions themselves.
>  
>
Yes, this is another very interesting observation and a practical one: 
the ADA people is *already* using it succesfully, it seems! We have only 
to investigate whether ADA exceptions are in any important way so 
different from C++ exceptions to make the example pointless.

Thanks Nathan,
Paolo.

(*) Frankly, I know almost nothing about ADA.