This reduces the symbols exported by libavformat from 699 to 451. Signed-off-by: Mans Rullgard <mans@mansr.com> (cherry picked from commit e62886403355614f0579a1568a53f04037c90df8)
Based on patch by Reinhard Tartler <siretart tauware de> Originally committed as revision 21236 to svn://svn.ffmpeg.org/ffmpeg/trunk