* Weekly U.S. jobless claims rise more than expected * July trade deficit falls to lowest level in five months * ECB hints at prolonging bond-buying program * Joy Global falls after slashing full-year forecast * Indexes up: Dow 0.89 pct, S&P 0.97 pct, Nasdaq 0.69 pct (Adds details, changes comment, updates prices) Sept 3 (Reuters) - Wall Street extended its gains on Thursday as data pointed to a strengthening U.S. economy and European Central Bank chief Mario Draghi hinted at additional stimulus measures. The ECB also cut its inflation and growth forecasts for the euro zone in the wake of lower oil prices, weaker growth in China and a strengthening euro. Draghi's remarks come a day ahead of the critical monthly U.S. jobs report, which may feed into the Federal Reserve's decision on the timing of a rate hike. The data is expected to show that the U.S. economy added 220,000 non-farm jobs in August, up from 215,000 in July, according to a Reuters poll of economists. The Fed, which meets on Sept. 16-17, has said it will raise rates when it sees sustained economic recovery. But while the labor market has strengthened, inflation remains below the Fed's... More