Maybe it needs to be renamed in the econf line too :/ $(use sse2 && use_enable cpu_flags_x86_sse sse) \
Yes, my mistake. Sorry. + 03 Feb 2015; Michał Górny <mgorny@gentoo.org> libvpx-1.3.0.ebuild, + libvpx-9999.ebuild: + Fix invalid flag USE=sse2 use, my mistake. Bug #538630.