NEWTOWN SQUARE, Pa. — Rory McIlroy had a one-word response when asked to describe his opening round at the PGA Championship: “S---.” He did go on to elaborate, but clearly a 74 at Aronimink Golf Club is not what the reigning Masters champion had in mind when the year’s second major championship began Thursday. McIlroy came into the tournament hoping to become the first player since Jordan Spieth in 2015 to win the first two major championships of the year. And McIlroy—who played with Spieth and Jon Rahm —was in decent shape when he birdied the fifth hole at Aronimink (his 14th of the day) to get back to even par for the round. Then he finished with four consecutive bogeys to shoot 74 on the par-70 layout. “I started missing fairways,” he said. “I missed the fairway right on [No. ] 4, the fairway right on 6, the fairway right on 7, fairway right on 9. From there, it’s hard—I didn’t have great angles either. Then obviously you start missing it just off the edges of these greens, it gets tricky.…