We have constants defined in several places (for example some in authorization_manager.h and others in sasl_client_authenticate.h - even though some of those in sasl_client_authenticate.h aren't sasl-specific). We also have some constants that are duplicates. We just need to generally clean up our constants in the security system.

See http://codereview.10gen.com/10014028/ for one example of using constants from SASL code outside of SASL code.