scummvm/scummvm — comment on commit 5af782c5d279b0b3b54ee041bb50c8fec2d35fd3
File: engines/scumm/saveload.cpp line 1301
By athrxx:

The problem is that all that data that gets saved and loaded here is neither declared nor processed in DISABLE_TOWNS_DUAL_LAYER_MODE mode. Of course, I could fill up the space in the savegame with zeroes.
But such a save file would obviously still not be good to load on any other port where the data is needed.

You might want to keep in mind that the DISABLE_TOWNS_DUAL_LAYER_MODE define is a specific memory saving measure that I added for the DS at the request of agentq. I don't think that the define will ever play a role for other ports.