RFC, fix for bogus timeouts in select()

[Andrew Lunn]

> - non-blocking reads here...
> - select() returns a timeout
> - read() returns data, even though select() immediately preceding it
> returned a timeout.

Since you are running on a pre-emptive multitasking OS, this is
expected behaviour. 

To know if there is a real bug here, we need to know when the data was
put into the socket relative to when select exited. Turning on tracing
will probably show this.

        Andrew