audio/libgroove: unbreak with ffmpeg 4.0

groove/encoder.c:619:59: error: use of undeclared identifier 'CODEC_CAP_VARIABLE_FRAME_SIZE'

e->sink->buffer_sample_count = (codec->capabilities & CODEC_CAP_VARIABLE_FRAME_SIZE) ?
                                                      ^

groove/file.c:284:66: error: use of undeclared identifier 'FF_INPUT_BUFFER_PADDING_SIZE'

uint64_t extra_size = (uint64_t)icodec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE;
                                                         ^

groove/playlist.c:189:63: error: use of undeclared identifier 'CODEC_CAP_DELAY'

if (!pkt_temp->data && dec->codec->capabilities & CODEC_CAP_DELAY)
                                                  ^

groove/playlist.c:574:55: error: use of undeclared identifier 'CODEC_CAP_DELAY'

if (f->audio_st->codec->codec->capabilities & CODEC_CAP_DELAY) {
                                              ^

groove/playlist.c:990:22: error: assigning to 'AVFilter *' (aka 'struct AVFilter *') from 'const AVFilter *' (aka 'const struct AVFilter *') discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

p->volume_filter = avfilter_get_by_name("volume");
                 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

groove/playlist.c:997:23: error: assigning to 'AVFilter *' (aka 'struct AVFilter *') from 'const AVFilter *' (aka 'const struct AVFilter *') discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

p->compand_filter = avfilter_get_by_name("compand");
                  ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

groove/playlist.c:1004:23: error: assigning to 'AVFilter *' (aka 'struct AVFilter *') from 'const AVFilter *' (aka 'const struct AVFilter *') discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

p->abuffer_filter = avfilter_get_by_name("abuffer");
                  ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

groove/playlist.c:1011:22: error: assigning to 'AVFilter *' (aka 'struct AVFilter *') from 'const AVFilter *' (aka 'const struct AVFilter *') discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

p->asplit_filter = avfilter_get_by_name("asplit");
                 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

groove/playlist.c:1018:23: error: assigning to 'AVFilter *' (aka 'struct AVFilter *') from 'const AVFilter *' (aka 'const struct AVFilter *') discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

p->aformat_filter = avfilter_get_by_name("aformat");
                  ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

groove/playlist.c:1025:27: error: assigning to 'AVFilter *' (aka 'struct AVFilter *') from 'const AVFilter *' (aka 'const struct AVFilter *') discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

p->abuffersink_filter = avfilter_get_by_name("abuffersink");
                      ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PR: 227726
Reported by: antoine (via exp-run)