avformat/smacker: use av_malloc_array() and check for allocation error

Signed-off-by: Paul B Mahol <onemda@gmail.com>
OpenCL: convert meaningless "device id" output to "device name"

Approved-by: Wei Gao <highgod0401@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>