There is a new pull request by ndowens against master on the void-packages repository

https://github.com/ndowens/void-packages docbook2mdoc
https://github.com/void-linux/void-packages/pull/16114

docbook2mdoc: update to 1.1.0
This version requires bsd/sys/queue.h
Link to bsd library to fix 'undefined reference to strtonum

A patch file from https://github.com/void-linux/void-packages/pull/16114.patch is attached