A union representing behind-the-scenes workers in Hollywood struck a deal with major film and TV studios on Saturday, preventing a nationwide strike that would have kicked off Sunday and could have crippled the entire industry. The International Alliance of Theatrical Stage Employees, which represents Hollywood crew members, and the Alliance of Motion Picture and Television Producers, which represents the studios, confirmed the news of an agreement to Deadline late Saturday. The two sides agreed to a three-year contract covering about 60,000 workers. “It took a lot to get here, but this is a good deal, a fair deal for everyone concerned,” a source familiar with the negotiations was quoted saying. “Time to break out the cigars.”