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

https://github.com/newbluemoon/void-packages lilypond
https://github.com/void-linux/void-packages/pull/23531

lilypond: update to 2.21.4
(obsolete: Tested 2.21.2 on x86_64, x86_64-musl, i686 and armv7l.)
Tested 2.21.3 on x86_64-musl.

A patch file from https://github.com/void-linux/void-packages/pull/23531.patch is attached