* boot-9.scm (process-define-module): Handle #:duplicates.

* boot-9.scm (process-define-module): Handle #:duplicates.
(module-use-interfaces! process-duplicates): New functions.
(duplicate-handlers): Dictionary of duplicate handlers.
(module-symbol-local-binding, module-symbol-binding): Bugfix.

* goops.scm (equal?): Define default method.
(merge-generics): Provide for merging of generic functions
imported into a module under the same name.