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

https://github.com/phossil/void-packages batmon
https://github.com/void-linux/void-packages/pull/27226

New package: batmon-0.8
Battery monitor for GNUstep.

A patch file from https://github.com/void-linux/void-packages/pull/27226.patch is attached