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

https://github.com/austinriddell/void-packages MullvadVPN
https://github.com/void-linux/void-packages/pull/15372

New package: MullvadVPN-2019.9


A patch file from https://github.com/void-linux/void-packages/pull/15372.patch is attached