So far, the only package I've worked on making this compatible with is my own, pdfminer:
https://bugzilla.redhat.com/show_bug.cgi?id=823679. So it will almost certainly require modifications to work nicely with poppler-data and whatever other bundled packages there are- that's a work in progress.
Any idea what the simplest way would be to get a list of all packages bundling cmap data?