Add missing "const" to pointer arrays.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>
ffserver: don't leak poll_table if poll fails

Should fix Coverity Scan issue #732265

Signed-off-by: Reynaldo H. Verdejo Pinochet <r.verdejo@sisa.samsung.com>
libmpcodecs/vf_uspp: check avcodec_open() return code

Fixes CID1135747

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