issue blocking input_handler

[James Browning]

> On 02/03/2023 2:51 PM PST Hal Murray <halmurray at sonic.net> wrote:
> 
> James Browning said:
> > I found a problem with input_handler(). If a reference clock passes a
> > blocking file descriptor, input_handler can block forever.
> 
> Who did that? Which driver?

I ran across it working on a chrony socket refclock. The scrap
is in merge request !1307. I have a suspicion about the gpsd
JSON driver as well.

> How about fixing the bug at ithe source rather than patching around it?

I tried and failed then I came up with that.