set dnsdomainname

[Marco van Hulten]

Hello Guix—

I want `dnsdomainname` to be set on my system with GuixSD (because it
is used as a destination in my Postfix configuration).  How do I go
about this?

The system with GuixSD gets network information from my Debian 8 server
that runs the ISC DHCP server.  So I thought the best approach would be
to configure the DHCP server by adding this near the top of dhcpd.conf:

    ddns-updates on;
    ddns-domainname "instanton";

But it doesn't get picked up by the GuixSD client system.

Is there a way to specify full hostname(1) information (`hostname
--fqdn`, `dnsdomainname`) in Guix' system configuration?

—Marco