libunistring: `u32_move` segfaults on musl

[tranzystorekk]

Is this a new report?

Yes

System Info

Void 5.19.10_1 x86_64-musl GenuineIntel/VM uptodate FF

Package(s) Affected

libunistring-1.0_1

Does a report exist for this bug with the project's home (upstream) and/or another distro?

No response

Expected behaviour

Tests for the boxes project run correctly

Actual behaviour

One of the tests segfaults (https://github.com/ascii-boxes/boxes/issues/103#issuecomment-1264611505)

Steps to reproduce

On a x86_64-musl void system (e.g. ghcr.io/void-linux/void-linux:latest-full-x86_64-musl):

1. xbps-install bison flex libunistring-devel pcre2-devel xxd git base-devel
2. git clone https://github.com/ascii-boxes/boxes
3. cd boxes && make && make test