Fix Julia 0.3.0 build (for most purposes). Not making default yet because it is unclear if I missed something important. Failed to make it use external openblas and lapack correctly…
nixos/radvd: Convert to a systemd unit

Additionally, remove the automatic initialization of the ipv6 forwarding
sysctl as this should be handled by the end user. This really should not
be an issue as most people running radvd are likely forwarding ipv6
packets.
nixos/radvd: Add to multi-user and wait for the network interfaces to be configured
radvd: Upsate 1.8.1 -> 2.5