fix highly theoretical source of crash.

bind_eressea now checks if bindings were called without filename

src/bind_eressea.c

@@ -28,15 +28,22 @@ void eressea_free_game(void) {
 }
 
 int eressea_read_game(const char * filename) {
+    if (filename) {
         return readgame(filename);
     }
+    return -1;
+}
 
 int eressea_write_game(const char * filename) {
+    if (filename) {
         remove_empty_factions();
         return writegame(filename);
     }
+    return -1;
+}
 
 int eressea_read_orders(const char * filename) {
+    if (filename) {
         FILE *F = fopen(filename, "r");
         int result;
 
@@ -49,8 +56,11 @@ int eressea_read_orders(const char * filename) {
         fclose(F);
         return result;
     }
+    return -1;
+}
 
 int eressea_export_json(const char * filename, int flags) {
+    if (filename) {
         FILE *F = fopen(filename, "w");
         if (F) {
             stream out = { 0 };
@@ -61,10 +71,12 @@ int eressea_export_json(const char * filename, int flags) {
             return err;
         }
         perror(filename);
+    }
     return -1;
 }
 
 int eressea_import_json(const char * filename) {
+    if (filename) {
         FILE *F = fopen(filename, "r");
         if (F) {
             stream out = { 0 };
@@ -75,5 +87,6 @@ int eressea_import_json(const char * filename) {
             return err;
         }
         perror(filename);
+    }
     return -1;
 }

src/volcano.c

@@ -80,7 +80,7 @@ int volcano_damage(unit* u, const char* dice)
 {
     int hp = u->hp / u->number;
     int remain = u->hp % u->number;
-    int ac, i, dead = 0, total = 0;
+    int ac = 0, i, dead = 0, total = 0;
     int healings = 0;
     const struct race* rc_cat = get_race(RC_CAT);
     int protect = inside_building(u) ? (building_protection(u->building) + 1) : 0;