linux_ioctl.[ch] : Implement LINUX_TIOCGPTN, which returns the pty number
linux_stats.c :
- Return the magic number for devfs.
- In various stats()-related functions, check that we're stating a
file in /dev/pts, and if so, change the st_rdev field to match what linux
expects to be there for a slave pty device. The glibc checks for this, and
their openpty() fails if it is no correct.