Robert Pluim writes:

> OK, that does make sense, and might even be more correct, but itʼs a
> bigger change. You'll need more than just me to agree with it.
>
Patch reworked:

 * before the select, check every interesting gnutls stream for
   available data in the buffer
 * if some of them hit, and either there is no wait_proc or the
   wait_proc is one of the gnutls streams with new data, set the select
   timeout to 0
 * after the select, merge the gnutls buffer status into the select
   returns

The patch is not much longer than before, still a net reduction of code
lines. I've done some light testing and haven't found any problem.