Brisket, sausage, turkey and smoked orange chicken at Brotherton’s Black Iron Barbecue in Pflugerville. (Photo ©Chris Wilkins/Texas BBQ Posse) Don’t know if Horace, the Roman poet who lived a couple thousand years ago, was a barbecue fan. But if he was and if he were around today, he would probably like Brotherton’s Black Iron Barbecue in Pflugerville. If for nothing else than the sign on the front window. “Carne Diem,” it says, a play on Horace’s immortal phase, “carpe diem,” commonly translated “seize the day.” The Brotherton’s sign is a mashup of Spanish and Latin. The joint translates the bilingual…