Use SWIFT_SDK_${sdk}_OBJECT_FORMAT to choose whether to use lipo and multi-arch builds

Author: kubamracek

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -501,7 +501,7 @@ function(_add_swift_lipo_target)
     list(APPEND source_binaries $<TARGET_FILE:${source_target}>)
   endforeach()
 
-  if(${LIPO_SDK} IN_LIST SWIFT_APPLE_PLATFORMS)
+  if("${SWIFT_SDK_${LIPO_SDK}_OBJECT_FORMAT}" STREQUAL "MACHO")
     if(LIPO_CODESIGN)
       set(codesign_command COMMAND "codesign" "-f" "-s" "-" "${LIPO_OUTPUT}")
     endif()