Well, the re-boot in progress seems to be moving in the right direction. FM, FD, FDSETUP, and FDNC now compile properly as they should.
Furthermore, they can talk to other FroDo:s, which is good. So the “commercial version” (which will be ditched, it’ll all be the same) can run in unlicensed mode. That’s one of the goals with this re-boot.
I also discovered that DOSbox-X plays very nicely with FrontDoor, even in a virtual Windows 10 32-bit environment under VirtualBox.