I am not planning on providing a mechanism tot stat() the database files
directly. The disadvantage of this, is that rwhod will now be a little
bit more heavy than it used to be. It normally used to fstat() the file
descriptor to see whether the file had changed, but this is now
impossible to implement, meaning we have to parse the entire utmp file
each 180 seconds.
This is probably not an issue on modern 16-way servers, but if it turns
out to be a problem, we'll think of something.
