The Romanian hacker whose illegal exploits first exposed Hillary Clinton’s use of a non-governmental e-mail system is set to waive extradition later this month so he can face trial in the United States on a nine-count felony indictment. Known as “Guccifer,†hacker Marcel Lehel Lazar, 43, is scheduled for a February 17 extradition hearing in Romania, where he has been jailed since his arrest in January 2014. Lazar is serving a four-year sentence for hacking into the e-mail accounts of several public figures in Romania, including the head of the country’s intelligence service. In a phone interview from a Bucharest...