Hardcode the address on all known platforms and skip it on unknown ones, or disassemble a public function that calls it and figure out the address from there, or read the Mach-O headers and write your own dlsym, etc. etc.
Apple once blocked a updates for everyone using a common SDK because it had named a symbol something that happened to be the name of an unrelated private API, and the review process couldn't tell the difference. That implies things about the rigor of the review process.