Remove the kernel PMC code. Sent yesterday on tech-kern@.

This change:

* Removes "options PERFCTRS", the associated includes, and the associated
ifdefs. In doing so, it removes several XXXSMPs in the MI code, which is
good.

* Removes the PMC code of ARM XSCALE.

* Removes all the pmc.h files. They were all empty, except for ARM XSCALE.

* Reorders the x86 PMC code not to rely on the legacy pmc.h file. The
definitions are put in sysarch.h.

* Removes the kern/sys_pmc.c file, and along with it, the sys_pmc_control
and sys_pmc_get_info syscalls. They are marked as OBSOL in kern,
netbsd32 and rump.

* Removes the pmc_evid_t and pmc_ctr_t types.

* Removes all the associated man pages. The sets are marked as obsolete.

branches: 1.17.16;
Add mips fenv.h (From FreeBSD)

branches: 1.16.4;
Rename sljitarch.h to sljit_machdep.h.

branches: 1.15.10;
Add sljit and bpfjit to evbmips. Not enabled by default.

branches: 1.14.2; 1.14.12;
Retire varargs.h support. Move machine/stdarg.h logic into MI
sys/stdarg.h and expect compiler to provide proper builtins, defaulting
to the GCC interface. lint still has a special fallback.
Reduce abuse of _BSD_VA_LIST_ by defining __va_list by default and
derive va_list as required by standards.

Switch MIPS and MIPS-ish architectures to new-style <sys/bus.h>. This
involves moving some inline bus_space(9) implementation into .c files.

Nuke a.out support for MIPS.

branches: 1.11.48;
Merge newlock2 to head.

branches: 1.10.4;
don't install <machine/db_machdep.h>, this is kernel only

branches: 1.9.4; 1.9.8;
merge ktrace-lwp.

branches: 1.8.12;
Factor out W{CHAR,INT}_{MAX,MIN} into their own header file.

branches: 1.7.2;
Merge the nathanw_sa branch.

Remove KDIR=, since SYS_INCLUDE=symlinks and KDIR are not supported any more.

Implement pmc(9) -- An interface to hardware performance monitoring
counters. These counters do not exist on all CPUs, but where they
do exist, can be used for counting events such as dcache misses that
would otherwise be difficult or impossible to instrument by code
inspection or hardware simulation.

pmc(9) is meant to be a general interface. Initially, the Intel XScale
counters are the only ones supported.

branches: 1.4.2;
Don't install intr.h isa_machdep.h pci_machdep.h rnd.h for userland.

branches: 1.3.2;
Don't install <machine/rnd.h>.

branches: 1.2.4;
Add ecoff_machdep.h for userland usage.

A port to the MIPS Malta evaluation board. Currently supports the
MIPS32 4Kc CPU board, with support for the MIPS64 5Kc and the QED RM5261
CPU boards to follow.

The cs4281 audio hasn't been tested, there are some interrupt problems
with onboard the pciide, but all other on-board peripherals work.

The evbmips port will support more MIPS evaluation boards in the future.

Add mips fenv.h (From FreeBSD)

branches: 1.16.4;
Rename sljitarch.h to sljit_machdep.h.

branches: 1.15.10;
Add sljit and bpfjit to evbmips. Not enabled by default.

branches: 1.14.2; 1.14.12;
Retire varargs.h support. Move machine/stdarg.h logic into MI
sys/stdarg.h and expect compiler to provide proper builtins, defaulting
to the GCC interface. lint still has a special fallback.
Reduce abuse of _BSD_VA_LIST_ by defining __va_list by default and
derive va_list as required by standards.

Switch MIPS and MIPS-ish architectures to new-style <sys/bus.h>. This
involves moving some inline bus_space(9) implementation into .c files.

Nuke a.out support for MIPS.

branches: 1.11.48;
Merge newlock2 to head.

branches: 1.10.4;
don't install <machine/db_machdep.h>, this is kernel only

branches: 1.9.4; 1.9.8;
merge ktrace-lwp.

branches: 1.8.12;
Factor out W{CHAR,INT}_{MAX,MIN} into their own header file.

branches: 1.7.2;
Merge the nathanw_sa branch.

Remove KDIR=, since SYS_INCLUDE=symlinks and KDIR are not supported any more.

Implement pmc(9) -- An interface to hardware performance monitoring
counters. These counters do not exist on all CPUs, but where they
do exist, can be used for counting events such as dcache misses that
would otherwise be difficult or impossible to instrument by code
inspection or hardware simulation.

pmc(9) is meant to be a general interface. Initially, the Intel XScale
counters are the only ones supported.

branches: 1.4.2;
Don't install intr.h isa_machdep.h pci_machdep.h rnd.h for userland.

branches: 1.3.2;
Don't install <machine/rnd.h>.

branches: 1.2.4;
Add ecoff_machdep.h for userland usage.

A port to the MIPS Malta evaluation board. Currently supports the
MIPS32 4Kc CPU board, with support for the MIPS64 5Kc and the QED RM5261
CPU boards to follow.

The cs4281 audio hasn't been tested, there are some interrupt problems
with onboard the pciide, but all other on-board peripherals work.

The evbmips port will support more MIPS evaluation boards in the future.