os/os.h has a default CPU_COUNT() inline function for those that
are expected to have CPU_COUNT() macro, but not in certain versions.
This seems to have been added for RHEL5 (or older?) and variants,
but use this in os/os-dragonfly.h since it's essentially the same
as its own fio_cpu_count() implementation.
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>