This patch adds a _curTick variable to an eventq. This variable is updated
whenever an event is serviced in function serviceOne(), or all events upto
a particular time are processed in function serviceEvents(). This change
helps when there are eventqs that do not make use of curTick for scheduling
events.
At the same time, rename the trace flags to debug flags since they
have broader usage than simply tracing. This means that
--trace-flags is now --debug-flags and --trace-help is now --debug-help
It's not the right fix for the checkpoint deadlock problem
Brad was having, and creates another bug where the system can
deadlock on restore. Brad can't reproduce the original bug
right now, so we'll wait until it arises again and then try
to fix it the right way then.
Added drain functions to the RTC and 8254 timer so that periodic interrupts
stop when the system is draining. This patch is needed to checkpoint in
timing mode. Otherwise under certain situations, the event queue will never
be completely empty.
