[libgpiod] Python bindings don't allow to wait on events indefinitely

[Nicolas Frattaroli <frattaroli.nicolas@gmail.com>]

Hello,

in libgpiod 1.6.x, Line.event_wait's codepath had no path where ts
as passed to ppoll could ever be NULL. This means waiting indefinitely
was impossible.

I thought hey, maybe the new Python bindings in libgpiod 2.x fixed this,
but no, it has made it worse by explicitly setting timeout to 0 seconds
if it's None[1]. Obviously, this behaviour can't be changed now, because
people depend on this API to return immediately now with None as the
parameter, and changing it to wait indefinitely would no doubt break
actual programs.

So I'm left wondering if there's a particular reason users of these
bindings shouldn't wait on events indefinitely or if that same mistake
was just made twice in a row.

Is there some way the API could be enhanced to support waiting for
events indefinitely without having to slap a While True with
an arbitrarily high timeout around every single invocation?

Regards,
Nicolas Frattaroli

[1]: https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/bindings/python/gpiod/internal.py#n11