The ZIP and EZIP interpreters for the Atari ST are combined
at the (68K) source level, using "conditional assembly" directives
wherever necessary.  These appear as follows:

    IFEQ EZIP
	*
	*
    ENDC

    IFEQ CZIP	* classic zip
	*
	*
    ENDC

    Searching for these strings will pinpoint most of the differences
between the two interpreters.