Gentoo's Bugzilla –
Attachment 564408 Details for
Bug 677604www-client/firefox-65.0 with media-libs/libvpx-1.8.0 - .../work/firefox-65.0/media/webrtc/trunk/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc:821:17: error: 'struct vpx_svc_ref_frame_config' has no member named 'frame_flags'