Score the fat on the pork loin roast in a diamond pattern.
Combine the crushed garlic, salt, ginger, cloves, and freshly ground pepper in a small bowl. Rub the spice mixutre into the scored fat on the roast; sprinkle with the bay leaves.
Pour 1/2 cup chicken broth and 1/2 cup rum into a shallow roasting pan. Place the roast, fat side up, on a rack in the roasting pan. Insert a meat thermometer into the thickest part of the roast, making sure it does not touch fat or bone. Bake at 325 degrees for 1 hour and 15 minutes.
Combine the remaining 1/2 cup rum, brown sugar, and lime juice in a small bowlp stir well. Baste the roast with the rum mixture, reserving any remaining rum mixture. Bake an additional 1 hour and 15 minutes.
Remove and discard the bay leaves. Transfer the roast to a serving platter. Set aside, and keep warm.
Add enough remaining 1 cup chicken broth to the remaining rum mixture to make 1 1/2 cups. Pour the liquid into a small heavy saucepan, and cook over medium heat until thoroughly heated. Combine the cold water and cornstarch; stir well. Stir cornstarch mixture into the broth mixture, stirring constantly. Cook over medium heat, stirring constantly, until the mixture is thickened and bubbly. Serve roast with the sauce.