Missing RNBOspro* symbols on Mac

I am updating our legacy components to Sentinel RMS 8.6.1. I can implement SuperPro hardware key support on Windows and Linux but this code is not linking on Macintosh. I am linking with liblssrv64.a and there are missing symbols:
Undefined symbols for architecture x86_64:
  "_RNBOsproFindFirstUnit", referenced from:
      _sc_initSuperPro in libspsslval.a(sctstsp.o)
  "_RNBOsproFindNextUnit", referenced from:
      _sc_initSuperPro in libspsslval.a(sctstsp.o)
  "_RNBOsproFormatPacket", referenced from:
      _sc_initSuperPro in libspsslval.a(sctstsp.o)
  "_RNBOsproGetVersion", referenced from:
      _sc_initSuperPro in libspsslval.a(sctstsp.o)
  "_RNBOsproInitialize", referenced from:
      _sc_initSuperPro in libspsslval.a(sctstsp.o)
  "_RNBOsproQuery", referenced from:
      _InterimU16Xlt in libspsslval.a(sctstsp.o)
      _sc_initSuperPro in libspsslval.a(sctstsp.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

How can I resolve these missing symbols? Is there another library I need to link?