Undefined symbols for architecture x86_64:
  "_Decoder_Interface_Decode",referenced from:
      DecodeAMRFileToWAVEFile(char const*,char const*) in amrFileCodec.o
  "_Decoder_Interface_exit",char const*) in amrFileCodec.o
  "_Decoder_Interface_init",char const*) in amrFileCodec.o
  "_Encoder_Interface_Encode",referenced from:
      EncodeWAVEFileToAMRFile(char const*,char const*,int,int) in amrFileCodec.o
  "_Encoder_Interface_exit",int) in amrFileCodec.o
  "_Encoder_Interface_init",int) in amrFileCodec.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command Failed with exit code 1 (use -v to see invocation)

* 选中Targets—>Build Settings—>Architectures。双击Architectures，选择other，删除$(ARCH_STANDARD)(点’-’)，然后增加armv7和armv7s(点‘+’)。clean一下再编译就行了。*

转载自 https://my.oschina.net/asjoker/blog/634510