aarg:
Perhaps you could ask the author of Arduino.h ...#define HIGH 0x1
#define LOW 0x0
#define INPUT 0x0
#define OUTPUT 0x1
Which has nothing whatsoever to do with the OPs question. Obviously, totally unrelated definitions will sometimes evaluate to the same numeric value, but the OP was explicitly asking how to give two names to the exact same value.
Regards,
Ray L.