Istanbul Mayor Ekrem Imamoglu said he's open to endorsing an alternative candidate if he’s prevented from contesting the next presidential election. Turkish President Recep Tayyip Erdogan’s strongest challenger has been in jail for almost five months and his comments signal how he's preparing for a long legal battle that could rule him out of the election. Bloomberg's Onur Ant reports. -------- More on Bloomberg Television and Markets Like this video? Subscribe and turn on notifications so you