for the system crontab file, pass a NULL pointer instead. This
prevents someone from creating a "*system*" file in the tabs directory
that acts as an alternate root crontab.
from openbsd
ended up _after_ the final '\0', so the code past though there are some
data to be passed to the spawned command, causing child process
crash under some circumstances; adjust input_data in this case to avoid this
XXX this is already fixed in cron 4.0-b1 (though slighly differently)
- ensure hostname from gethostname() is nul-terminated in all cases
- minor KNF
- use MAXHOSTNAMELEN over various other values/defines
- be safe will buffers that hold hostnames