As I type these lines there are rumors that “Mud,” by the American Jeff Nichols, may find its way to the top rungs of the competition prizes—some are even talking of a Palme D’Or upset. Matthew McConaughey, who came to the Croisette to present a film for the first time in his career, plays the Mud of the title, an enlightened vagabond living on a deserted island on the Mississipi river—his past is heavy with blunders. Two independent-