There is an updated pull request by jjsullivan5196 against master on the void-packages repository

https://github.com/jjsullivan5196/void-packages squeekboard
https://github.com/void-linux/void-packages/pull/24375

New package: squeekboard-1.9.3
#24072 will be the first port to a mobile phone, so some mobile graphical elements such as onscreen keyboards will be needed. Squeekboard is maintained by the Librem5 team at purism, and is the choice for most non-kde wayland environments such as wlroots compositors, GNOME 3 (Phosh), etc. It has been used extensively in postmarketos and the pinephone port of Archlinux ARM. 

I've tested it running inside sway on x86_64 and aarch64 cross-compiled. Basic typing and DBus/protocol activation both work.

A patch file from https://github.com/void-linux/void-packages/pull/24375.patch is attached