(Adds details, background) By Fiona Ortiz CHICAGO, Oct 6 (Reuters) - A Chicago-area man was charged on Monday with attempting to support a foreign terrorist organization after he was arrested on Saturday at O'Hare International Airport on allegations he was on his way to Syria to join the militant group Islamic State. Mohammed Hamzah Khan, 19, of the Chicago suburb of Bolingbrook, appeared before U.S. Magistrate Susan Cox in U.S. District Court in Chicago, and she ordered him held pending a detention hearing on Thursday. ...