macOS has never defined the usual endian(3)/byteorder(9) byte-swapping functions. This change implements these byte-swapping functions using the OSSwap functions, which provide identical functionality. This was tested on macOS 10.15.7. Change-Id: I44d59869a4420030f3ce26118175304c680d57a1 Signed-off-by: Alex James <theracermaster@gmail.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/60219 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Julius Werner <jwerner@chromium.org> Reviewed-by: Angel Pons <th3fanbus@gmail.com>