To enable use with online Bulletin Board Systems (BBSes) where users
may be disconnected unexpectedly, but would naturally want to resume
playing their same game, added support for an optional save game
path/filename to be specified on the command-line (very similar to
"-r <filename>"), except this save/restore file is:
1. automatically loaded/restored if it exists
2. automatically created when starting a new game
3. automatically updated when exiting a game for any reason
4. cannot be changed to a different path/filename by the user
Since a BBS server program can be expected to send a SIGHUP or SIGTERM
to the game process upon user disconnection (or timeout), those
signals are caught and a graceful termination will occur which saves
the current game state.
Build with ADVENT_AUTOSAVE defined to enable this option.
BUG:
The 'info' command still reports the save/suspend/pause commands as
valid, though they are not when this build option is used (same is
true of ADVENT_NOSAVE, and that doesn't apparently bother anyone).
Note. because we used fixed-length declrations in the right places, this
shouldn't break saves.
(Besides being right, this will someday make a port to Go a touch easier,
if we decide to do that.)
* Remove disused macro.
* GCC doesn't seem to mind if IGNORE() is left off.
* Enumify phase codes.
* Use EXIT_* macros in all exit() calls.
* How did this even work without extern?
* Give advent.h a much-needed makeover.
* Use the chomp indicator in YAML string blocks to avoid code ugliness.
For a project this small size with a small type ontology, it's better
C style to have one header where all the assumptions about types and
structures are immediately visible.
This is a first step towards turning all that global state into a handful
of structures - probably just two, one saveable as a binary game state.
