Georg Koppen authored May 22, 2017 and Alex Catarineu committed Sep 15, 2020

In the past the ClearKey system had not been compiled when specifying
--disable-eme. But that changed and it is even bundled nowadays (see:
Mozilla's bug 1300654). We don't want to ship it right now as the use
case for it is not really visible while the code had security
vulnerabilities in the past.