Undefined symbols for architecture armv7:

  "_deflate", referenced from:

      -[BDTTSGzipCompressor compressBytes:length:shouldFinish:] in libbdtts.a(BDTTSGzipCompressor.o)

  "_deflateEnd", referenced from:

      -[BDTTSGzipCompressor closeStream] in libbdtts.a(BDTTSGzipCompressor.o)

  "_deflateInit2_", referenced from:

      -[BDTTSGzipCompressor setupStream] in libbdtts.a(BDTTSGzipCompressor.o)

ld: symbol(s) not found for architecture armv7

clang: error: linker command failed with exit code 1 (use -v to see invocation)