Very basic carbons support is hacked into mcabber. Messages are now intercepted and parsed. It probably makes more sense to implement XEP-0297: Stanza Forwarding in a more general way. A better way to display the carbons (so the user actually knows it is a carbon message) is in the pipeline.

#ifndef __MCABBER_CARBONS_H__
#define __MCABBER_CARBONS_H__ 1

void carbons_init();
void carbons_available();
void carbons_enable();
void carbons_disable();

#endif //__MCABBER_CARBONS_H__