Something

gcc -L./libavformat -L./libavcodec -L./libavutil -rdynamic -g -o ffmpeg_g ffmpeg.o cmdutils.o -lavformat -lavcodec -lavutil -lm -lsocket -lnsl -lz
gcc: unrecognized option `-rdynamic'
Undefined                       first referenced
 symbol                             in file
wav_codec_get_id                    ./libavformat/libavformat.a(nuv.o)
adpcm_xa_decoder                    ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ct_decoder                    ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ea_decoder                    ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ms_decoder                    ./libavcodec/libavcodec.a(allcodecs.o)
pcm_u8_demuxer                      ./libavformat/libavformat.a(allformats.o)
pcm_s8_demuxer                      ./libavformat/libavformat.a(allformats.o)
url_close_dyn_buf                   ./libavformat/libavformat.a(movenc.o)
adpcm_xa_encoder                    ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ct_encoder                    ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ea_encoder                    ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ms_encoder                    ./libavcodec/libavcodec.a(allcodecs.o)
pcm_u16be_demuxer                   ./libavformat/libavformat.a(allformats.o)
pcm_u16le_demuxer                   ./libavformat/libavformat.a(allformats.o)
adpcm_ima_ws_decoder                ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_qt_decoder                ./libavcodec/libavcodec.a(allcodecs.o)
voc_get_packet                      ./libavformat/libavformat.a(avs.o)
adpcm_ima_ws_encoder                ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_qt_encoder                ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_yamaha_encoder                ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_yamaha_decoder                ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_4xm_encoder                   ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_swf_encoder                   ./libavcodec/libavcodec.a(allcodecs.o)
get_wav_header                      ./libavformat/libavformat.a(asf.o)
adpcm_adx_encoder                   ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_g726_encoder                  ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_swf_decoder                   ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_4xm_decoder                   ./libavcodec/libavcodec.a(allcodecs.o)
voc_demuxer                         ./libavformat/libavformat.a(allformats.o)
adpcm_ima_smjpeg_decoder            ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_dk3_decoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_dk4_decoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_sbpro_2_encoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_sbpro_4_encoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_sbpro_3_encoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_wav_decoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_sbpro_2_decoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_sbpro_4_decoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_sbpro_3_decoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_wav_encoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_dk3_encoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_dk4_encoder               ./libavcodec/libavcodec.a(allcodecs.o)
adpcm_ima_smjpeg_encoder            ./libavcodec/libavcodec.a(allcodecs.o)
pcm_s16be_demuxer                   ./libavformat/libavformat.a(allformats.o)
pcm_s16le_demuxer                   ./libavformat/libavformat.a(allformats.o)
url_open_dyn_buf                    ./libavformat/libavformat.a(movenc.o)
pcm_mulaw_demuxer                   ./libavformat/libavformat.a(allformats.o)
pcm_alaw_demuxer                    ./libavformat/libavformat.a(allformats.o)
ld: fatal: Symbol referencing errors. No output written to ffmpeg_g
collect2: ld returned 1 exit status
gmake: *** [ffmpeg_g] Error 1