MAXHOSTNAMELEN and the MIN/MAX macros. We now use PATH_MAX and
HOST_NAME_MAX throughout without falling back on MAXPATHLEN or
MAXHOSTNAMELEN and define our own MIN/MAX macros as needed.
file is owned by the right user, not world-writable and not writable
by a group other than the one specified at configure time (gid 0
by default), the file is considered OK. Note that visudo will still
set the mode to the value specified at configure time.