cmdutils: fix build with --disable-avfilter.
lavfi/curves: make use of options to store the preset names.
ffmpeg: initialize got_output, this silences a compiler warning from icc

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
cavsdsp: fix "warning: initialization discards const qualifier from pointer target type"

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