cmake链接ffmpeg静态链接库 undefined reference错误

利用cmake生成makefile文件编译项目时出现undefined reference错误，导致编译失败，经网上资料的查询可知需要调整ffmpeg库的连接顺序libavformat、libavdevice、libavcodec、libavutil、libpthread、libswscale、libswresample。

完成顺序调整后，如果仍出现以下报错，则说明未将libswresample链接至程序文件，导致报错。

/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_decode_subpacket':
../ffmpeg/libavcodec/opusdec.c:346: undefined reference to `swr_is_initialized'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_decode_frame':
../ffmpeg/libavcodec/opusdec.c:187: undefined reference to `swr_is_initialized'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_init_resample':
../ffmpeg/libavcodec/opusdec.c:135: undefined reference to `swr_init'
../ffmpeg/libavcodec/opusdec.c:141: undefined reference to `swr_convert'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_decode_frame':
../ffmpeg/libavcodec/opusdec.c:201: undefined reference to `swr_convert'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_flush_resample':
../ffmpeg/libavcodec/opusdec.c:89: undefined reference to `swr_convert'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_decode_subpacket':
../ffmpeg/libavcodec/opusdec.c:378: undefined reference to `swr_close'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_decode_flush':
../ffmpeg/libavcodec/opusdec.c:581: undefined reference to `swr_close'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_decode_close':
../ffmpeg/libavcodec/opusdec.c:605: undefined reference to `swr_free'
/usr/local/lib/libavcodec.a(opusdec.o): In function `opus_decode_init':
../ffmpeg/libavcodec/opusdec.c:674: undefined reference to `swr_alloc'
collect2: error: ld returned 1 exit status
CMakeFiles/***.dir/build.make:167: recipe for target '***' failed
make[2]: *** [***] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/***/all' failed
make[1]: *** [CMakeFiles/***.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2

重新将所有链接库链接配置修改后生成编译，便完成ffmpeg的链接与编译