/* Creates and returns a casegrouper that reads data from READER
and breaks it into contiguous groups of cases that have equal
values for the VAR_CNT variables in VARS. If VAR_CNT is 0,
/* Creates and returns a casegrouper that reads data from READER
and breaks it into contiguous groups of cases that have equal
values for the VAR_CNT variables in VARS. If VAR_CNT is 0,