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

zathura-pdf-mupdf: update to 0.3.9.
https://github.com/void-linux/void-packages/pull/40131

Description:
#### Testing the changes
- I tested the changes in this PR: **YES**

#### Local build testing
- I built this PR locally for my native architecture, x86_64

This PR contains quite a few changes to get around issues discussed in https://github.com/void-linux/void-packages/issues/35634. It works in my system but if someone could test it in musl (cc @dkwo) that would be useful.