Log Message:
lang/python and a number of python packages: re-do atomic64.mk issue.

Evidently, python 3.13 brought in the need to support 64-bit atomics.
This means that python extension packages built with C needs to
use mk/atomic64.mk to make -latomic available on the required 32-bit
ports.  Sadly, there is no reliable way to detect in the .mk files
whether the package is using C (or C++), so this change adds an
unconditional include of mk/atomic64.mk when the python version is
equal to or larger than 3.13 for packages using egg.mk or wheel.mk.

This undoes the individual package Makefile inclusions of mk/atomic64.mk
that I've added over the last few days.