Carl Reiner has accumulated lots of plaudits over his seven decades in the entertainment industry as a writer, producer, director and actor. But alongside his work on the seminal television series “Your Show of Shows” and “The Dick Van Dyke Show” and his directing on films that include “The Jerk” and “All of Me,” Reiner can now claim another designation: At 96, he’s the oldest person ever nominated for a Primetime Emmy Award.