BUENOS AIRES--Argentine President Mauricio Macri, who has maintained close ties with Donald Trump for many years, warned against optimism that the U.S. president-elect will take a flexible stance after his inauguration. “(Trump) is a bold and aggressive person who pushes his pet theories and pushes through them,” Macri, 57, said in an exclusive interview with The Asahi Shimbun on Nov. 18, before Japanese Prime Minister Shinzo Abe’s official visit to Argentina. Like Trump, 70, Macri used to be a businessman. He has gotten to know Trump’s personality and management skills since the 1980s. During the U.S. election campaign, Macri expressed...