(svn r13376) -Feature: Add access to current long year and date from Action 7/9/D and VarAction2 (23/24 or A3/A4)

Add access to (long format) building year, in Variational Action2 Variable 49 for Vehicles

src/newgrf.cpp

@@ -3648,6 +3648,14 @@ bool GetGlobalVariable(byte param, uint32 *value)
 			*value = _settings_game.difficulty.diff_level;
 			return true;
 
+		case 0x23: // long format date
+			*value = _date;
+			return true;
+
+		case 0x24: // long format year
+			*value = _cur_year;
+			return true;
+
 		default: return false;
 	}
 }