In file included from ./libavutil/common.h:48,
                 from ./libavutil/avutil.h:301,
                 from ./libavutil/opt.h:31,
                 from libavdevice/sdl2.c:31:
./config.h:334: warning: 'HAVE_PTHREAD_SETNAME_NP' redefined
 #define HAVE_PTHREAD_SETNAME_NP 0
 
In file included from /usr/include/SDL2/SDL_stdinc.h:31,
                 from /usr/include/SDL2/SDL_main.h:25,
                 from /usr/include/SDL2/SDL.h:32,
                 from libavdevice/sdl2.c:26:
/usr/include/SDL2/SDL_config.h:188: note: this is the location of the previous definition
 #define HAVE_PTHREAD_SETNAME_NP 1
 
libavfilter/af_volumedetect.c: In function 'process_float_planar_samples':
libavfilter/af_volumedetect.c:55:13: error: implicit declaration of function 'update_float_stats' [-Werror=implicit-function-declaration]
             update_float_stats(vd, &audio_data[i]);
             ^~~~~~~~~~~~~~~~~~
libavfilter/af_volumedetect.c: In function 'process_int_planar_samples':
libavfilter/af_volumedetect.c:84:15: error: 'VolDetectContext' {aka 'struct VolDetectContext'} has no member named 'nb_samples'
             vd->nb_samples++;
               ^~
libavfilter/af_volumedetect.c: In function 'process_int_packed_samples':
libavfilter/af_volumedetect.c:99:15: error: 'VolDetectContext' {aka 'struct VolDetectContext'} has no member named 'nb_samples'
             vd->nb_samples++;
               ^~
At top level:
libavfilter/af_volumedetect.c:89:13: warning: 'process_int_packed_samples' defined but not used [-Wunused-function]
 static void process_int_packed_samples(VolDetectContext *vd, AVFrame *samples)
             ^~~~~~~~~~~~~~~~~~~~~~~~~~
libavfilter/af_volumedetect.c:74:13: warning: 'process_int_planar_samples' defined but not used [-Wunused-function]
 static void process_int_planar_samples(VolDetectContext *vd, AVFrame *samples)
             ^~~~~~~~~~~~~~~~~~~~~~~~~~
libavfilter/af_volumedetect.c:60:13: warning: 'process_float_packed_samples' defined but not used [-Wunused-function]
 static void process_float_packed_samples(VolDetectContext *vd, AVFrame *samples)
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
libavfilter/af_volumedetect.c:46:13: warning: 'process_float_planar_samples' defined but not used [-Wunused-function]
 static void process_float_planar_samples(VolDetectContext *vd, AVFrame *samples)
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
make: *** [ffbuild/common.mak:81: libavfilter/af_volumedetect.o] Error 1
make: *** Waiting for unfinished jobs....