(svn r26790) [1.4] -Backport from trunk:

- Fix: Loading a game with order backups leaked Orders and left unreachable items in the pool (r26787)
- Fix: Buffer overrun in SQCompiler::Error (r26764)
- Fix: Desync due to not always properly restoring game state from the savegame (r26753)
- Fix: [Script] Crashes and infinite loops when using lists in item-descending order [FS#6085] (r26744)

src/script/api/script_list.cpp

@@ -354,7 +354,12 @@ public:
 			this->has_no_more_items = true;
 			return;
 		}
-		this->item_iter--;
+		if (this->item_iter == this->list->items.begin()) {
+			/* Use 'end' as marker for 'beyond begin' */
+			this->item_iter = this->list->items.end();
+		} else {
+			this->item_iter--;
+		}
 		if (this->item_iter != this->list->items.end()) item_next = (*this->item_iter).first;
 	}