OPEC and non-OPEC producers led by Russia agreed on Thursday to extend oil output cuts until the end of 2018 as they try to finish clearing a global glut of crude while signaling a possible early exit from the deal if the market overheats. Russia, which this year reduced production significantly with OPEC for the first time, has been pushing for a clear message on how to exit the cuts so the market doesn’t flip into a deficit too soon, prices don’t rally too fast and rival U.S. shale firms don’t boost output further. Sponsored Russia needs much lower oil prices to balance its budget than OPEC’s leader Saudi Arabia, which is preparing a stock market listing for national energy champion Aramco next year and would hence benefit from pricier crude. The producers’ current deal, under which they are cutting supply by about 1.8 million barrels […]