Set/unset support for duplicate keys

#include "btree.h"

int btdups(BTA* btact, int dups);

The btdups controls support for duplicate keys in the current root of the index file associated with the btact context pointer. Setting the value of the dups to non-zero (TRUE) will enable support for duplicate keys in the current root. A value of zero (FALSE) will disable duplicate key support for the current root. Enabling duplicate key support on the superroot is not permitted.

Disabling duplicate key support on a root that previously permitted them merely prevents further duplicate keys from being inserted into the root BTree index. Existing duplicates will remain and must be managed by the application.

A non-zero return code indicates an error occurred.