Not strictly a dependency, but would still be logical to solve first: #45563
As mentioned in #46442, building redundancy handling needs to be added. Likely also update to is_building_needed() (haven't checked, but it's a bit similar functionality)
Reply To cazfi
building redundancy handling needs to be added.
That's done in attached version. validity.c was fine.
#45832 will do little good, if there's no BuildingFlag requirement type to use those custom flags.