So looks like the tests have been somehow at fault, as they are compiled against libpostal in some ultra weird manner. So for now I've hard-disabled them (dropped their compilation from the makefile) and the build finally runs to the end. This should be good for now, later one for the actual package review something more robust (possibly including reporting the issue upstream) might be needed. I'll open a PR for the libpostal packaging soon, just have to cleanup my changes a bit. Anyway, as far as I can tell this concludes the missing dependencies & I can finally start packaging OSM Scout Server itself.