Gentoo's Bugzilla –
Attachment 396236 Details for
Bug 539854media-plugins/alsa-plugins-1.0.28 with media-video/libav-11.2 - .libs/rate_lavcrate.o: In function `pcm_src_free': .../work/alsa-plugins-1.0.28/rate-lavc/rate_lavcrate.c:70: undefined reference to `av_resample_close'