The entertaining PBS portrait of composer Marvin Hamlisch, aptly titled, “What He Did For Love,” provides the music, his method for creating it, and the man. Fortunately for producer Dori Berinstein, and for us, Hamlisch was often photographed and the footage of him performing, accepting awards, Pulitzer, Oscars, Emmys, Tonys, so much a part of our recent cultural history, makes our loss all the more poignant: he died a little more than a year ago at age 68, clearly with much more music to give.