Jake Gyllenhall, who’s been in Boston for the film “Stronger’’ (inspired by the story of Boston Marathon bombing survivor Jeff Bauman), was at the Wilbur Theatre on Saturday night to see Nick Kroll and John Mulaney’s final Boston performance of “Oh, Hello.’’ We’re told that the actor made time to go backstage and hang with the show’s stars. According to The Hollywood Reporter, Gyllenhaal has signed on to produce “Stronger,’’ and now has financing for the project from Bold Films. That company’s catalog includes “Whiplash,’’ “Lost River,’’ and Gyllenhaal’s “Nightcrawler.’’