The new RTC framework hasn't been very usable on most x86 desktop
PCs ... so here's a driver using the ACPI RTC and PNPACPI.  AFAICT
it could mostly replace drivers/char/rtc.c on ACPI systems.

One of the goals here was to expose this RTC as a normal wakeup
event source ... no /proc/acpi/alarm thing, just the same userspace
interfaces as on non-ACPI RTCs, and non-RTC devices.  That works
somewhat ... for the very first time, I've seen ACPI wakeup behave!

But ACPI doesn't always behave after hardware wakeup events, so

	echo disabled > /sys/class/rtc/rtc0/device/power/wakeup

may be appropriate on the systems where it doesn't yet work.

- Dave

p.s. A followup message will include a userspace program which
     makes it easier to try the RTC wakeup mechanism.