rtspcodes: don't check for >0 on error codes macro

Avoids a warning with gcc 4.7 and -Wtype-limits. Albeit
superfluous (At least gcc 4.8 didnt consider this been
a problem).

Signed-off-by: Reynaldo H. Verdejo Pinochet <r.verdejo@sisa.samsung.com>
avcodec/libopencore-amr: use av_mallocz_array()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/libzvbi-teletextdec: remove * 1

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/j2kenc: use av_malloc(z)_array()

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