pyconfig: Better comment associated with HAVE_DEV_PTMX and HAVE_DEV_PTC
pyconfig: Better comment associated with HAVE_DEV_PTMX and HAVE_DEV_PTC

For reference, see python/cpython@0cd89332

davidsansome/python-cmake-buildsystem,thewtex/python-cmake-buildsystem,python-cmake-buildsystem/python-cmake-buildsystem,msmolens/python-cmake-buildsystem,chuckatkins/python-cmake-buildsystem,thewtex/python-cmake-buildsystem,jcfr/python-cmake-buildsystem,adrianbroher/python-cmake-buildsystem