After a generous grace period of one and a half months, polyclipping removed previously deprecated parts of the API. If possible, please try to support this new API, so that we can continue to ship polyclipping as a package without modification.
Citing the changelog:
v6.0.0 (30 October 2013): * Deprecated: Version 6 is a major upgrade from previous versions and quite a number of changes have been made to exposed structures and functions. To minimize inconvenience to existing library users, some code has been retained and some added to maintain backward compatibility. However, because this code will be removed in a future update, it has been marked as deprecated and a precompiler directive use_deprecated has been defined.
v6.1.0 (12 December 2013) * Deleted: Previously deprecated code has been removed.