Adding a macro to define the vlog module in use adds a level of
indirection, which makes it easier to change how the vlog module must be
defined. A followup commit needs to do that, so getting these widespread
changes out of the way first should make that commit easier to review.
Every so often I get concerned because OVS does most of its time arithmetic
in "long long int" but poll_timer_wait() takes an "int", so there is
potential for truncating a large value to a small value or a positive value
to a negative value. That would cause excessive wakeups and possibly 100%
CPU usage.
This commit therefore changes poll_timer_wait()'s parameter type from "int"
to "long long int". The file-scope 'timeout' variable remains type "int"
because that is the type of poll()'s timeout argument.
Factoring poll_timer_wait() into two functions is not necessary here but it
comes in handy in the following patch.
The last user of this feature has been removed, so delete the feature too,
simplifying poll-loop.c significantly.
poll_cancel() is no longer used, either, but deleting it is much less
beneficial.
Rather than running signal hooks directly from the actual signal
handler, simply record the fact that the signal occured and run
the hook next time around the poll loop. This allows significantly
more freedom as to what can actually be done in the signal hooks.
