NAME
        GetUniqueID -- return a relatively unique number. (V39)

   SYNOPSIS
        id = GetUniqueID();
        D0

        ULONG GetUniqueID(VOID);

   FUNCTION
        Returns a unique value each time it is called. This is useful for
        things that need unique ID such as the GadgetHelp ID, etc.
        Note that this is only unique for 4,294,967,295 calls to this
        function. Under normal use this is not a problem.
        This function is safe in interrupts.

   RESULT
        id - a 32-bit value that is unique.