UltraRogue: add the autosave feature.

UltraRogue now automatically saves the game when SIGHUP or SIGTERM is
received.

urogue/main.c

@@ -197,6 +197,8 @@ main(int argc, char *argv[])
 												  
     food_left = (int) (food_left * scale);
 
+    md_onsignal_autosave();
+
     /* Set up windows */
 
     cw = newwin(LINES, COLS, 0, 0);
@@ -272,6 +274,12 @@ fatal(char *s)
     exit(100);
 }
 
+void
+fatal_handler(int sig)
+{
+    fatal("");
+}
+
 /*
     rnd()
         Pick a very random number.

urogue/mdport.c

@@ -1271,3 +1271,43 @@ md_readchar(WINDOW *win)
 
     return(ch & 0x7F);
 }
+
+extern void auto_save(int sig);
+extern void fatal_handler(int sig);
+extern void quit_handler(int sig);
+
+void
+md_onsignal_autosave(void)
+{
+#ifdef SIGHUP
+    signal(SIGHUP, auto_save);
+#endif
+#ifdef SIGQUIT
+    signal(SIGQUIT, fatal_handler);
+#endif
+#ifdef SIGTERM
+    signal(SIGTERM, auto_save);
+#endif
+#ifdef SIGINT
+    signal(SIGINT, quit_handler);
+#endif
+    return;
+}
+
+void
+md_ignore_signals(void)
+{
+#ifdef SIGHUP
+    signal(SIGHUP, SIG_IGN);
+#endif
+#ifdef SIGQUIT
+    signal(SIGQUIT, SIG_IGN);
+#endif
+#ifdef SIGTERM
+    signal(SIGTERM, SIG_IGN);
+#endif
+#ifdef SIGINT
+    signal(SIGINT, SIG_IGN);
+#endif
+    return;
+}

urogue/rogue.h

@@ -1813,6 +1813,8 @@ void md_srandom(long seed);
 int md_readchar(WINDOW *win);
 int md_getuid(void);
 void md_normaluser(void);
+void md_onsignal_autosave(void);
+void md_ignore_signals(void);
 
 #define NOOP(x) (x += 0)
 #define CCHAR(x) ( (char) (x & A_CHARTEXT) )

urogue/save.c

@@ -115,6 +115,18 @@ save_savedir_game(void)
     }
 }
 
+void
+auto_save(int sig)
+{
+    FILE *savef;
+
+    md_ignore_signals();
+    if (file_name[0] && (savef = fopen(file_name, "w"))) {
+        save_file(savef);
+    }
+    exit(0);
+}
+
 int
 restore(char *file)
 {