how do you set up a linux client to use ntp information provided through dhcp?

If the dhcp server you are using is configured to provide the ntp-servers option, you can configure your dhclient to request ntp-servers by adding ntp-servers to the default request line in dhclient.conf, as shown at the end of this example from Ubuntu Linux (as of 19.04, but present since at least 12.04):

request subnet-mask, broadcast-address, time-offset, routers,
        domain-name, domain-name-servers, domain-search, host-name,, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
        netbios-name-servers, netbios-scope, interface-mtu,
        rfc3442-classless-static-routes, ntp-servers;

/etc/ntp.conf and the information from DHCP will be used to create /etc/ntp.conf.dhcp.

Your ntpd must be told to use /etc/ntp.conf.dhcp if it exists. On the version of Ubuntu that I'm using, this is done via /etc/dhcp/dhclient-exit-hooks.d/ntp. <-- this is the file that tells NTPd to use /etc/ntp.conf.dhcp if it exists, and to just use /etc/ntp.conf if it doesn't.