Late to the game, but this might help someone...

I don't recommend this in a production environment, but it would be fine for e.g. a home lab.

I built qemu from source on another host (in my case, on a laptop running Ubuntu Mate):

./configure --static
make

... and then sftp'd the generated qemu-img executable to the XCP-ng host (I didn't care about any other outputs from the build process, some of which failed anyway likely due to the ancient version of Ubuntu Mate running on my laptop).

Building with --static avoided any issues with missing libraries on the XCP-ng host, at least for qemu-img.