Import OpenBSD's sysctl hardware sensors framework.

This commit includes the following core components:

 * sample configuration file for sensorsd
 * rc(8) script and glue code for sensorsd(8)
 * sysctl(3) doc fixes for CTL_HW tree
 * sysctl(3) documentation for hardware sensors
 * sysctl(8) documentation for hardware sensors
 * support for the sensor structure for sysctl(8)
 * rc.conf(5) documentation for starting sensorsd(8)
 * sensor_attach(9) et al documentation
 * /sys/kern/kern_sensors.c
   o sensor_attach(9) API for drivers to register ksensors
   o sensor_task_register(9) API for the update task
   o sysctl(3) glue code
   o hw.sensors shadow tree for sysctl(8) internal magic
 * <sys/sensors.h>
 * HW_SENSORS definition for <sys/sysctl.h>
 * sensors display for systat(1), including documentation
 * sensorsd(8) and all applicable documentation

The userland part of the framework is entirely source-code
compatible with OpenBSD 4.1, 4.2 and  -current as of today.

All sensor readings can be viewed with `sysctl hw.sensors`,
monitored in semi-realtime with `systat -sensors` and also
logged with `sensorsd`.

Submitted by:	Constantine A. Murenin <cnst@FreeBSD.org>
Sponsored by:	Google Summer of Code 2007 (GSoC2007/cnst-sensors)
Mentored by:	syrinx
Tested by:	many
OKed by:	kensmith
Obtained from:	OpenBSD (parts)

1 files changed, 1 insertions, 1 deletions

diff --git a/usr.bin/systat/Makefile b/usr.bin/systat/Makefile
index 4f5f229725b6..2c7592a960c7 100644
--- a/usr.bin/systat/Makefile
+++ b/usr.bin/systat/Makefile
@@ -5,7 +5,7 @@
 
 PROG=	systat
 SRCS=	cmds.c cmdtab.c devs.c fetch.c iostat.c keyboard.c main.c \
-	mbufs.c netcmds.c netstat.c pigs.c swap.c icmp.c \
+	mbufs.c netcmds.c netstat.c pigs.c sensors.c swap.c icmp.c \
 	mode.c ip.c tcp.c \
 	vmstat.c convtbl.c ifcmds.c ifstat.c