cpuminer-opt-3.19.0

Windows binaries for CPUs with AVX2 and newer are now built with support for CPU groups, requires Windows 7.

Changes to cpu-affinity:

• PR#346: Fixed incorrect CPU affinity on Windows built for CPU groups,
• added support for CPU affinity for up to 256 threads or CPUs,
• streamlined code for more efficient initialization of miner threads,
• precise affining of each miner thread to a specific CPU,
• added an option to disable CPU affinity with "--cpu-affinity 0"

Faster sha256t with AVX512 & AVX2.

Added stratum error count to stats log, reported only when non-zero.

Note: Windows binaries have been rebuilt for CPUs with AVX, SSE* due to problems with CPU groups.
cpuminer-opt-3.19.0-windows2.zip contains rebuilt binaries without support for CPU groups for those builds.
There are no source code changes and no changes to other builds.