mp3dec: fallback to generic seeking when a TOC is not present

Fixes seeking without a Xing/Info header.

CC: libav-stable@libav.org
Signed-off-by: Anton Khirnov <anton@khirnov.net>
(cherry picked from commit 505642f18276aed03278ac91b1f334ea888eac6a)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
oggdec: fix faulty cleanup prototype

(cherry picked from commit fba8e5b608577fc660989d0057a55818254a3744)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
riff: check for eof if chunk size and code are 0

Prevent an infinite loop.

Inspired by a patch from Michael Niedermayer

CC: libav-stable@libav.org

Signed-off-by: Diego Biurrun <diego@biurrun.de>
(cherry picked from commit 8e329dba378cef0ff6400c7df9c51da167d5a1f0)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>