For those who think the Hamptons International Film Festival hibernates during February, think again. The festival that never sleeps will present, in partnership with Guild Hall, a screening of Robert Altman’s 1971 classic “McCabe and Mrs. Miller,” on Saturday at 7 p.m. at the John Drew Theater. Alec Baldwin, the festival’s co-chairman, and David Nugent, its artistic director, will host a discussion after the screening.