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

https://github.com/hadrianw/void-packages master
https://github.com/void-linux/void-packages/pull/12456

zbar: fix qt option handling
The option in configure is called qt not qt5.

A patch file from https://github.com/void-linux/void-packages/pull/12456.patch is attached