Improved the performance of kernel profiling on MULTIPROCESSOR, and possible to get profiling data for each CPU.

In the current implementation, locks are acquired at the entrance of the mcount
internal function, so the higher the number of cores, the more lock conflict
occurs, making profiling performance in a MULTIPROCESSOR environment unusable
and slow. Profiling buffers has been changed to be reserved for each CPU,
improving profiling performance in MP by several to several dozen times.

- Eliminated cpu_simple_lock in mcount internal function, using per-CPU buffers.
- Add ci_gmon member to struct cpu_info of each MP arch.
- Add kern.profiling.percpu node in sysctl tree.
- Add new -c <cpuid> option to kgmon(8) to specify the cpuid, like openbsd.
For compatibility, if the -c option is not specified, the entire system can be
operated as before, and the -p option will get the total profiling data for
all CPUs.

use explicit cast for RHS of shift operator since semantics change from
traditional c to ansi.

branches: 1.9.88; 1.9.92;
delete ROUNDUP/ROUNDDOWN; they don't belong here and ROUNDUP is a copy
of roundup in <sys/param.h>

branches: 1.8.20; 1.8.22;
merge ktrace-lwp.

branches: 1.7.16;
Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22364, verified by myself.

branches: 1.6.62;
Allow default HISTFRACTION to be overriden by port-specific definition.

fix extra spaces at ends of lines, etc. (all spacing nits.)

New RCS ID's, take two. they're more aesthecially pleasant, and use 'NetBSD'

new standard, minimally intrusive ID format

Add RCS ids.

branches: 1.1.1;
lots of changes: prototype migration, move lots of variables, definitions,
and structure elements around. kill some unnecessary type and macro
definitions. standardize clock handling. More changes than you'd want.