unimrcp make 编译出现下面错误

[sevenler]

src/xfyun_synth_engine.c:311:35: warning: passing 'const void *' to parameter of type 'void *' discards
qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
mpf_buffer_audio_write(buffer, data, audio_len);
^~~~
../../libs/mpf/include/mpf_buffer.h:43:63: note: passing argument to parameter 'data' here
apt_bool_t mpf_buffer_audio_write(mpf_buffer_t *buffer, void *data, apr_size_t size);
^
1 warning generated.
CCLD xfyunsynth.la
ld: library not found for -lrt
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [xfyunsynth.la] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all-recursive] Error 1

关键词也google不出来相关信息，不知道问题出在了哪里，求教！！