[geofft]

I think I like that solution! It doesn't work if someone replaces /etc/localtime with a new file, but it works if they update it in place. It's low-overhead as long as /etc/localtime remains in cache; the process that updates it will write to the same pages. It's pretty high-overhead if /etc/localtime ever gets flushed from cache, though, since you have to go out to disk.