- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Locking for todr got pushed down into inittodr and the client
libraries it calls (although some might not be doing it right). We are
serialized right now by giant as well. This means the splsoftclock are
now an anachronism that has no benefit, even marking where locking
needs to happen. Remove them.

style(9) nit: remove unnecessary {} pair.

Now that all platforms use genclock, shuffle things around slightly
for better structure.

Much of this is related to <sys/clock.h>, which should really have
been called <sys/calendar.h>, but unless and until we need the name,
the repocopy can wait.

In general the kernel does not know about minutes, hours, days,
timezones, daylight savings time, leap-years and such. All that
is theoretically a matter for userland only.

Parts of kernel code does however care: badly designed filesystems
store timestamps in local time and RTC chips almost universally
track time in a YY-MM-DD HH:MM:SS format, and sometimes in local
timezone instead of UTC. For this we have <sys/clock.h>

<sys/time.h> on the other hand, deals with time_t, timeval, timespec
and so on. These know only seconds and fractions thereof.

Move inittodr() and resettodr() prototypes to <sys/time.h>.
Retain the names as it is one of the few surviving PDP/VAX references.

Move startrtclock() to <machine/clock.h> on relevant platforms, it
is a MD call between machdep.c/clock.c. Remove references to it
elsewhere.

Remove a lot of unnecessary <sys/clock.h> includes.

Move the machdep.disable_rtc_set sysctl to subr_rtc.c where it belongs.
XXX: should be kern.disable_rtc_set really, it's not MD.

First part of a little cleanup in the calendar/timezone/RTC handling.

Move relevant variables to <sys/clock.h> and fix #includes as necessary.

Use libkern's much more time- & spamce-efficient BCD routines.

Add some missing <sys/module.h> includes which are masked by the
one on death-row in <sys/kernel.h>

Use __FBSDID().

Add an identify method that creates a pmtimer0 device if it doesn't alreedy
exist. Hints are no longer needed to instantiate a pmtimer(4) device.

Reenable RTC interrupts after wakeup. Some laptops have a problem
with system statistics monitoring tools (such as systat, vmstat...)
because of stopping RTC interrupts generation.
Restore all the timers (RTC and i8254) atomically.

Reviewed by: bde
MFC after: 1 week

Add Timer device driver for power management events.
The code for suspend/resume is derived from APM device driver.

Some people suggested the original code is somewhat buggy, but I'd
like to just move it from apm.c without any major changes for the
initial version. This code should be refined later.

To use pmtimer to adjust time at resume time, add
device pmtimer
in your kernel config file, and add
hint.pmtimer.0.at="isa"
in your device.hints

Reviewed by: -current, bde