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

https://github.com/Akaricchi/void-packages sdl2-mixer-opus
https://github.com/void-linux/void-packages/pull/15470

SDL2_mixer: enable Opus support
Required for #15467

A patch file from https://github.com/void-linux/void-packages/pull/15470.patch is attached