check_c_source_compiles("
            #ifdef NEWFFMPEGAVCODECPATH
            #include <libavcodec/avcodec.h>
            #else
            #include <ffmpeg/avcodec.h>
            #endif
            int main() {
            #if LIBAVCODEC_BUILD >= AV_VERSION_INT(54,25,0)
            # Not needed here. AV_CODEC_ID_MP3 exists.
            #else
            enum CodecID t = CODEC_ID_MP3;
            #endif
            return 0;
            }
            " HAVE_FFMPEG_CODEC_MP3)