Hello, I was frustrated with blank pages on my moodle installation, and then I realized my php was compiled with -session. Please consider adding this flag to the PHP_REQUIRED_FLAGS_* variable, thanks.
Okay, it can't hurt to add it. Note that php has IUSE="+session" so the user has to go out of the way to turn it off. Still, I can see that choice causing problems for moodle, so forcing it may be the right way. The ebuilds will be on the tree in a little bit. Please test and reopen this bug if you hit a problem.