In a large saucepan or Dutch oven, cook the salt pork or bacon until crisp. Add onions and cook until they soften somewhat, about 4 or 5 minutes. Sprinkle flour over the onions, add bay leaves and thyme; increase the heat to high. Pour in wine and stir to loosen brown bits from the bottom of the pan. Cook for about 2 minutes, or until wine has evaporated.