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

https://github.com/void-power/void-packages linux
https://github.com/void-linux/void-packages/pull/12815

add patches to fix kernels on ppc64 BE with gcc9
See the comment in the patches for rationale. This will be reported and hopefully fixed upstream, for now we need a workaround, this one is fortunately pretty simple.

A patch file from https://github.com/void-linux/void-packages/pull/12815.patch is attached