Oil majors Exxon Mobil XOM.N and Chevron Corp CVX.N slipped 0.6% and 0.3%, respectively, tracking crude prices. By Devik Jain Oct 20 (Reuters) - U.S. stock index futures struggled for direction on Wednesday as investors weighed the impact of supply chain constraints and inflation on corporate earnings, while Netflix shares remained sluggish after its quarterly report. Netflix's NFLX.O global sensation "Squid Game" helped lure more customers than expected, the world's largest streaming service said as it predicted a packed lineup would further boost signups through the end of the year.