D26050: Fix build with poppler 82

[René J.V. Bertin]

>  I am a firm +1 on splitting Calligra

+++
At the very least, the build system should be able to generate the shared parts as well as the different components (wordprocessor, spreadsheet, ...) separately (and depending on the installed shared libraries, for the components). Once that's done it should be possible to reorganise the source tree so releases can consist of separate tarballs for the shared bits and the individual applications even if you'll continue to use a single git repo (which would probably make sense).