COMMON: Add error for unsupported manual save slot #3369
I believe it would be easier to write protect the autosave slot instead.
We already have support for this, e.g. check agi/metaengine.cpp:303:
Currently looking into that and have a tentative implementation ready, but I will test a bit more. Also I've discovered another save game related bug (basically save deletion bug) that I intend to fix.
From what I understand, setting the slot as write protected will disable the option to "Save" in it, rename it or "Delete" it. It does not show any message when attempting to do any of these actions, but the buttons get disabled.
I think it's close enough to what I want so I will close this PR in favor of the setWriteProtectedFlag() approach.