ALBANY, N.Y. - Cartoonist Johnny Hart, whose award-winning “B.C.” comic strip appeared in more than 1,300 newspapers worldwide, died at his home on Saturday. He was 76.“He had a stroke,” Hart’s wife, Bobby, said on Sunday. “He died at his storyboard.”“B.C.,” populated by prehistoric cavemen and dinosaurs, was launched in 1958 and eventually appeared in more than 1,300 newspapers with an audience of 100 million, according to Creators Syndicate, Inc., which distributes it.