Swingers influenced a wave of bad 1990s boyfriends. Released 30 years ago today, the Jon Favreau film is an entertaining bit of macho posturing that became a cult film for the boys who needed to grow up. It’s another Clinton-era tale of Gen-X slackerdom, featuring pop-culture-obsessed twentysomethings trying to hold on to their hipness as they head into adulthood kicking and screaming. (See Slacker, Singles, Reality Bites, any ’90s movie starrin…