There's a merged pull request on the void-packages repository

libass: update to 0.15.0
https://github.com/void-linux/void-packages/pull/25952

Description:
Pretty big release, patches a few low-severity vulnerabilities. https://github.com/libass/libass/releases/tag/0.15.0

Tested on: `x86_64`,  `i686`, `x86_64-musl`.

Was unable to test on `i686-musl` because building `m4` fails for whatever reason, will have to sort that out but no reason it shouldn't work.