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

https://github.com/gspe/void-packages lyx
https://github.com/void-linux/void-packages/pull/27713

lyx: update to 2.3.6.1 and replace old enchant
It compile fine.
I don't use lyx so I haven't tested the spell check but should works fine.

A patch file from https://github.com/void-linux/void-packages/pull/27713.patch is attached