MAIDUGURI, Nigeria — Buji Abdullahi and his family managed to escape the deadly attack on his village by the militant Islamic group Boko Haram, but then he lost his young son to another scourge sweeping through the relief camps in northeastern Nigeria: a desperate lack of food.In a land where people have endured more than their share of tragedy and loss in recent years, the specter of famine is posing a cruel new threat. “I watched my 2-year-old son, Hashimu, die from hunger,” said Mr. Abdullahi. “It was sad, but there was nothing I could do to save him.”
