+An -a command-line option has been added (comditionally on
+ADVENT_AUTOSAVE) for use in BBS door systems. When this option is
+given, the game roads from the specified filename argument on startup
+and saves to it on quit or a received signal. There is a new nmessage
+to inform the user about this.
+
+The game can be built in a mode that entirely disables save/resume
+(-DADVENT_NOSAVE). If the game had been built this way, a diagnostic is
+emitted if you try to save or resume.
+