The autosave refactoring that was done in
7adad5aaf5 used g_engine for identifying the
autosave slot. This worked for in-game save/load, but doesn't fit when
called from the launcher.
Fix by passing MetaEngine to SaveStateDescriptor ctor and using it for this
query.
Amends 7adad5aaf5.
Some engines call setAutosave and some don't. isAutosave is used to
determine if a saved game is an autosave, but in fact, on most cases it
just falls back to comparing the name to "Autosave".
This is wrong for several reasons:
* Older versions of ScummVM used Autosave 0.
* The name "Autosave" is translated, so if you change the language, it
won't be detected.
Instead of relying on the name, use the well-known getAutosaveSlot() from
Engine/MetaEngine.
Fixes#12735.
For each engine:
- Make a new folder detection
- Move detection-related files inside the folder
- Add a new module "enginename/detection"
- Add DETECT_OBJS here
- Adjust the normal engine module to remove detect_objs
- Adjust every file for the new changes.
