avcodec/jacosubdec: use time_internal.h, simplify code

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/segment: use time_internal.h, simplify code

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/wavenc: Use localtime_r() for thread saftey

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/sbgdec: Use localtime_r() for thread saftey

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/img2enc: Use localtime_r() for thread saftey

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