These may be "good enough" for big-endian systems that do not have assembly
language versions of their own. A compiler should be able to do a fairly
good job optimising them, it probably won't be smart enough to omit the
stack frame, but then again, these functions won't be called unless the
macro versions are undef'd.
On the other hand, they are only intended for bootstrap purposes on little-
endian systems. They should be replaced with assembly language versions as
soon as possible.