Probably most people just run ntpd or ntpdate from time to time, so readline is not strictly needed. Reproducible: Always
Created attachment 400254 [details, diff] ntp_readline.patch
should be all set now in the tree; thanks for the report! Commit message: Control readline dep via USE flag http://sources.gentoo.org/net-misc/ntp/ntp-4.2.8-r3.ebuild?rev=1.1