There is an updated pull request by shahab-vahedi against master on the void-packages repository

https://github.com/shahab-vahedi/void-packages inetutils-fix-missing-whois-service-in-iana
https://github.com/void-linux/void-packages/pull/18520

inetutils: fix the missing port number for whois
Fixes issue 18445:
https://github.com/void-linux/void-packages/issues/18445

inetutils-whois consults the /etc/services provided by IANA to
determine the port number for the "whois" service. However, the
"whois" service is not listed in that file and when you run whois
you will end up with the following error:

> whois 4.2.2.4
  getaddrinfo: Servname not supported for ai_socktype

This patch makes use of "nicname" port which is the same number
(43) as a "whois" port and is listed in /etc/services. Moreover,
I have added "help2man" as the "hostmakedepends". Usually, you
don't need to have it running, but if you touch the whois.c file,
then the build process needs it.

A patch file from https://github.com/void-linux/void-packages/pull/18520.patch is attached