libmusicbrainz: 5.1.0 -> 5.1.0-unstable-2025-07-12
Last stable release in 2014, trickle of mundane fix commits since
then, including CMake 4 support. Try not to think about how long ago
the 3.x version was released, by the way.
Diff: https://github.com/metabrainz/libmusicbrainz/compare/release-5.1.0...4efbed3afae11ef68281816088d7cf3d0f704dfe