[Patch] Fix libstdc++/11378 (3rd take)

[Paolo Carlini]

Nathan Myers wrote:

>I don't see the above
>as a reason to delay applying the patch.  Since the problem is in 
>the existing code, and doesn't affect 11378, there's no reason not
>to apply it and close 11378.  (I suppose I should file a bug report
>detailing this problem.)
>
Thanks for bringing up the issue! I don't think it's necessary to file a 
bug report: I'm already working on the problem, which seems quite clear. 
Indeed, providing a wrapper for write seems quite simple, that for 
writev is a little more complex, but I have found around some code to 
study and adapt to our needs (just google for xwritev ;).

Thanks again,
Paolo.