Commit 1.8 in profiles/default/linux/make.defaults removed some USE flags, that were readded with commit 1.9. The problem is that the variable definition was re-added at the beginning of the file, so the next definition now overrides it. Trivial fix: add ${USE} in the second USE variable definition at line 20 :)
Fixed by olemarkus: http://sources.gentoo.org/viewvc.cgi/gentoo-x86/profiles/default/linux/make.defaults?r1=1.11&r2=1.12