C question

It’s possible to write some C code to work out whether a machine’s architecture is little-endian or big-endian with respect to bytes. Is it possible, using only ANSI C, to work out whether the machine’s architecture is big-endian or little-endian with respect to bits? I don’t know the ANSI spec in nearly as much pedantic detail as would be necessary to answer the question, but I bet someone does.