`final' is a boolean indicating whether local parts should be looked
up using the system-global rules.
`home' is a home directory to set, which is useful if filter files are
being used.
m4_define(<:VHOST_FILTER:>,
<:FILTER_BASE
VHOST(<:$1:>)
+ router_home_directory = DOMKV(home, {$value} fail)
+ more = ${if bool{DOMKV(final, {$value}{true})} {false} {true}}
$2 = ${expand:DOMKV($1, {$value} fail)}:>)
m4_define(<:VHOST_USER:>,
<:user = DOMKV(owner, {$value}{CONF_filter_user})