fix for socket timeouts (and a question about _Jv_select)

[Jeff Sturm]

Tom Tromey wrote:
> Yeah.  What this means is that select() examines the slots in the
> vector numbered 0, 1, ..., nfds-1.  If you pass `1' as nfds, then
> select() will only look at the settings for fd 0.  This is a goofy
> interface.  Maybe we ought to use poll() instead.  I don't know.  I
> use select() since I have a bsd-ish background.

select() is more portable, usually.  It should also work on Winsock, to
answer another question...

Jeff