Deb package includes broken symlink instead of manual

The Ubuntu package does not include the manual - instead, it contains a broken symlink:

❯ file /usr/share/doc/mixxx/Mixxx-Manual.pdf
/usr/share/doc/mixxx/Mixxx-Manual.pdf: broken symbolic link to ../mixxx-data/Mixxx-Manual.pdf

Using locate, I found that there is no proper version on my machine.

This holds true for at least the package in the mixxxbetas ppa: https://launchpad.net/~mixxx/+archive/ubuntu/mixxxbetas

I inspected the package files - while the .tar.gz contains the Mixxx-Manual.pdf, in the .deb there is only the broken symlink as /usr/share/doc/mixxx/Mixxx-Manual.pdf, with no notion of a mixxx-data dir.

Upon inspecting the build/debian directory in the source tree, I suspect that the fix might be as easy as deleting build/debian/mixxx.links, but I don't know how to test this assumption.