benchmarks/libcpucycles20260901

benchmarks/libcpucycles: update to 20260901

Changelog: https://cpucycles.cr.yp.to/download.html

Event:		Berlin Hackathon 202609

benchmarks/libcpucycles: update to 20260625

This fixes a Linux-specific issue with no changes affecting FreeBSD.

Changelog: https://cpucycles.cr.yp.to/download.html

benchmarks/libcpucycles: update to 20260105

Changelog: https://cpucycles.cr.yp.to/download.html

benchmarks/libcpucycles: update to 20251226

Changelog: https://cpucycles.cr.yp.to/download.html

Event:		39C3

benchmarks/libcpucycles: update to 20250925

Changelog: https://cpucycles.cr.yp.to/download.html

Event:		EuroBSDcon 2025

benchmarks/libcpucycles: report actual CPU frequency if supported

This uses sched_getcpu(2) to find the CPU we are scheduled on and then
cpufreq(4) to find the frequency of that CPU.  The caller is responsible
for pinning the thread to one CPU and/or disabling frequency scaling if
a consistent result is required.

benchmarks/libcpucycles: fix jmpbuf / sigjmpbuf confusion

I forgot to include this patch originally.  While the warning is
harmless (sigjmp_buf and jmp_buf have the same layout on FreeBSD),
it might not be on downstream ports consumers like DragonflyBSD.

benchmarks/libcpucycles: Microlibrary for counting CPU cycles

libcpucycles is a microlibrary for counting CPU cycles.  Cycle counts
are not as detailed as Falk diagrams but are the most precise timers
available to typical software; they are central tools used in
understanding and improving software performance.

The libcpucycles API is simple: include <cpucycles.h>, call cpucycles()
to receive a long long whenever desired, and link with -lcpucycles.

Internally, libcpucycles understands machine-level cycle counters for
amd64 (both PMC and TSC), arm32, arm64 (both PMC and VCT), mips64,
ppc32, ppc64, riscv32, riscv64, s390x, sparc64, and x86. libcpucycles
also understands four OS-level mechanisms, which give varying levels of
accuracy: mach_absolute_time, perf_event, CLOCK_MONOTONIC, and, as a
fallback, microsecond-resolution gettimeofday.

When the program first calls cpucycles(), libcpucycles automatically
benchmarks the available mechanisms and selects the mechanism that does
the best job.  Subsequent cpucycles() calls are thread-safe and very
fast. An accompanying cpucycles-info program prints a summary of
cycle-counter accuracy.

WWW: https://cpucycles.cr.yp.to/

Tested by:	jhibbits