In r585 we got rid of one of the major uses [redirect()] of the
server_name, server_port and server_path configuration options. They're
still used in a few places, but it's few enough that I think it's worth the
effort to remove these configuration options entirely, if we can't think of
a good reason against doing so.

/admin/settings.php - Getting/Setting each option
/register.php - Generate a URL for e-mail activation links; this is the
only major use of these options.
/viewnews.php - Auto-linking relative URLs? I honestly have no idea what
purpose this serves.