Fix -rpath linker option for Apple build (pytorch#13850)

Fix for pytorch#12333 which broke mac
runner tests on trunk, since `$ORIGIN` is linux only.

Author: jackzhxng

examples/models/llama/CMakeLists.txt

@@ -219,6 +219,8 @@ endif()
 target_include_directories(llama_main PUBLIC ${_common_include_directories})
 target_link_libraries(llama_main PUBLIC llama_runner ${link_libraries})
 target_compile_options(llama_main PUBLIC ${_common_compile_options})
-if(NOT APPLE)
+if(APPLE)
+  target_link_options(llama_main PRIVATE -Wl,-rpath,@executable_path)
+elseif(UNIX)
   set_target_properties(llama_main PROPERTIES LINK_FLAGS "-Wl,-rpath='$ORIGIN'")
 endif()