Add os.NODEV #138712
Description
NODEV is not a part of Posix, but it is defined as (dev_t)-1 on many systems (in particularly, on Linux, FreeBSD, NetBSD, OpenBSD, OpenIndiana). It is used to denote non-existing or undefined value for dev_t values.
On Linux, FreeBSD and OpenIndiana major(NODEV), minor(NODEV) and makedev(NODEV, NODEV) return NODEV. Unfortunately, this is not so on NetBSD and OpenBSD, but anyway it can be useful.