Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

/* -> /*- for copyright notices, minor format tweaks as necessary

Remove __P.

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

$Id$ -> $FreeBSD$

Remove unneeded prototypes.

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Cleaned up all headers that include <sys/ioctl.h> or <sys/ioccom.h>:
- don't include <sys/ioctl.h> in any header. Include <sys/ioccom.h>
instead. This was already done in 4.4Lite for the most important
ioctl headers. Header spam currently increases kernel build
times by 10-20%. There are more than 30000 #includes (not counting
duplicates) for compiling LINT.
- include <sys/types.h> if and only it is necessary to make the header
almost self-sufficient (some ioctl headers still need structs from
elsewhere).
- uniformized idempotency ifdefs. Copied the style in the 4.4Lite
ioctl headers.

Add support for Pentium and Pentium Pro performance counters.
(This code is as yet untested; to come after man page is written.)
This also adds inlines to cpufunc.h for the RDTSC, RDMSR, WRMSR, and RDPMC
instructions. The user-mode interface is via a subdevice of mem.c;
there is also a kernel-size interface which might be used to aid
profiling.