avformat/mov: Simplify code by using OFFSET() and FLAGS macros

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/libxvid_rc: Avoid strerror() for thread saftey

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/dvdsubdec: Avoid strerror() due to thread saftey

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>