Gentoo's Bugzilla –
Attachment 578680 Details for
Bug 687294www-client/firefox-67.0 - .../work/firefox-67.0/media/webrtc/trunk/webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc:869:17: error: 'struct vpx_svc_ref_frame_config' has no member named 'frame_flags'