Remove never used ifdefs, define FATAL macro properly and define function
parameters in modern way.

Stop using __P macro.

Remove the use of cast. It is unnecessary and potentially problematic.

input semarie
ok deraadt

Add missing $OpenBSD$ tags.

add $OpenBSD$ and remove trailing space. no functional change.

Initial import npppd(8). npppd is a new PPP daemon that handles many
ppp sessions as a server. It supports L2TP, PPTP and PPPoE as
tunneling.

ok mcbride@ dlg@ deraadt@ reyk@.