Hi,
(please don't use 680613, as your won't show up on the pkg-multimedia
archives and I cannot easily reply)
I've dropped the multi-arch headers now in this commit:
http://anonscm.debian.org/gitweb/?p=pkg-multimedia/libav.git;a=commitdiff;h=a55d079b01da2c81de68af0ebdb86d07aec5f5c7
--
regards,
Reinhard