LONDON–China’s property sector woes could spell trouble for prestige mega-projects in London, New York, Sydney and other top cities as the developers behind them scramble for cash. While China Evergrande Group’s struggles have dominated the crisis, the risk to multi-trillion dollar global property markets stems from some of its rivals that have spent the last decade competing to build ever taller and grander skyscrapers. Shanghai-based Greenland Holdings, which breaches as many of China’s debt “red lines” as Evergrande, has just built Sydney’s tallest residential tower, has plans to do the same in London, and has billions of dollars worth of projects in Brooklyn, Los Angeles, Paris, and Toronto. The developer says it remains committed to its flagship builds including its long-delayed, 235 metre-high Spire London tower, but it put part of another major London site on the market earlier in the year and other firms are hoisting for sale signs …