Melt butter in a large Dutch oven over medium-high heat. Once melted, add the garlic and onions and saute until soft, about 5 minutes.Stir in the tomatoes, chicken stock, barbecue sauce, Worcestershire, brown sugar, cayenne, smoked pork, lima beans, corn and salt and pepper.Bring the mixture to a boil, then reduce to a simmer and cook over medium-low heat for 1½ hours, stirring occasionally.