HOWTO let lighttpd listen to both IPv4 and IPv6 requests on *BSD

Problem
When enabling IPv6 using server.use-ipv6 = "enable", lighttpd no longer listens to IPv4 requests.

Solution
Set a sysctl knob so that it will accept both IPv4 and IPv6 requests:

root@soulfury:~# sysctl net.inet6.ip6.v6only=0