I am not a QT or X11 guy but from looking at the patch it seems like the primary purpose of those maemo changes in QT5 (the ones the patch wants to get rid of) is to implement support for various Maemo-specific wierdness to do with input. Possibly the answer going forward is to change the rest of the system so it is no longer non-standard and will work out of the box with the standard QT5 system.