There is a new pull request by q66 against master on the void-packages repository

https://github.com/void-ppc/void-packages higan-newco
https://github.com/void-linux/void-packages/pull/13312

higan: add a new implementation of libco for ppc64 ELFv2
Void uses ELFv2, and thanks to this we no longer need to fall back to the slow sjlj portable implementation.

The patch has been upstreamed: https://github.com/byuu/higan/pull/9

A patch file from https://github.com/void-linux/void-packages/pull/13312.patch is attached