so remove argc and argv from main() argument.
At the same time, user and tt is not likely to be changed during
execution so mark them const.
This commit should guarantee nologin to pass WARNS=6.
Tested on: i386
MFC After: 1 month
nologin(8), this causes a considerable (100K) increase in the binary size,
so I've added a NO_LOGIN_LOG option which disables this.
While I'm here, s/sizeof(MESSAGE)/sizeof(MESSAGE) - 1/, in order to
avoid writing the string-terminating zero byte.
No complaints from: -current
Approved by: rwatson (mentor)
