Adam Lambert sounds carnivorous, and more than a little carnal, in his new single, “Eat U Alive,” which just came out Friday. But what he’s hungered after most in his recent music-making is the spirit he thinks best thrived in the ’90s and early 2000s, when there was an easy crossover between electronic music and alternative rock. He’s aiming to have that same kind of fruitful blend be the basis of his sixth full-length album, “Adam,” which will arrive July 10. “It’s basically a rock song with electronic production,” Lambert says of “Eat U Alive.” He admits that’s partly a youthful fixation, given his own coming-of-age in the ’90s. Fans who first experienced him doing more rock-oriented material, via “American Idol” or as a Queen frontman or just in some of his early records, may embrace “Eat U Alive” and “Adam” marking a turn toward the rockier.…