Always #define _PyLong_FromDev as we always need it to compile rather than

only defining it when HAVE_MKNOD && HAVE_MAKEDEV are true.

This "oops" issue reported by John E. Malmberg on core-mentorship.
(what kinds of systems don't HAVE_MKNOD && HAVE_MAKEDEV?)

diff --cc Modules/posixmodule.c
Simple merge