[LinuxPPS] moving PPS create into PPSAPI

[clemens at dwf.com]

moving the set line discipline into the PPSAPI has been mentioned
a couple of times, but I dont see how this is possible.

the

        time_pps_create (fd, &pps_h)

command needs the file descriptor of the PPS device, which implies
that it is already open.  That being the case, hiding its creation below
this call is going to be impossible.

One would have to extend the PPSAPI in some way, and this gets 
back into all the compatability problems we have seen before.
-- 
                                        Reg.Clemens
                                        reg at dwf.com