Butter a large piece of heavy-duty foil. Peel squash if necessary. Cut into 1"x1"x2" spears. Slice other veggies extremely thin to reduce cooking time. Place veggies in center of foil. Mash the garlic with the salt, sprinkle over veggies. Sprinkle other spices on. Drizzle with olive oil or butter. Seal packets so they won't leak. Place over medium coals for 30-40 minutes, turning occasionally.