Kept busy as a support in big, international films, playing a Harry Potter eccentric or a Troy toga patriarch, Brendan Gleeson is a star character actor in Ireland. In Bruges, written and directed by Martin McDonagh, showed a film could profitably be built around his baggy, clear-eyed disappointment, especially if he gets reams of barbed, whimsical, profane, brutally funny dialogue. The Guard, written and directed by John Michael McDonagh, Martin’s brother, is another blend of shaggy-dog story and genre picture,…