(Pdb) bt
  bin/emerge(51)<module>()
-> retval = emerge_main()
  pym/_emerge/main.py(1057)emerge_main()
-> return run_action(emerge_config)
  pym/_emerge/actions.py(4069)run_action()
-> emerge_config.args, spinner)
  pym/_emerge/actions.py(320)action_build()
-> settings, trees, myopts, myparams, myaction, myfiles, spinner)
  pym/_emerge/depgraph.py(8449)backtrack_depgraph()
-> myaction, myfiles, spinner)
  pym/_emerge/depgraph.py(8481)_backtrack_depgraph()
-> success, favorites = mydepgraph.select_files(myfiles)
  pym/_emerge/depgraph.py(3131)select_files()
-> return self._select_files(args)
  pym/_emerge/depgraph.py(3467)_select_files()
-> return self._resolve(myfavorites)
  pym/_emerge/depgraph.py(3622)_resolve()
-> self.altlist()
  pym/_emerge/depgraph.py(6267)altlist()
-> self._resolve_conflicts()
  pym/_emerge/depgraph.py(6394)_resolve_conflicts()
-> self._process_slot_conflicts()
  pym/_emerge/depgraph.py(1241)_process_slot_conflicts()
-> self._solve_non_slot_operator_slot_conflicts()
  pym/_emerge/depgraph.py(1208)_solve_non_slot_operator_slot_conflicts()
-> self._create_graph()
  pym/_emerge/depgraph.py(2031)_create_graph()
-> allow_unsatisfied=allow_unsatisfied):
  pym/_emerge/depgraph.py(2639)_add_pkg_deps()
-> allow_unsatisfied):
  pym/_emerge/depgraph.py(2655)_add_pkg_dep_string()
-> allow_unsatisfied)
  pym/_emerge/depgraph.py(2804)_wrapped_add_pkg_dep_string()
-> allow_unsatisfied=allow_unsatisfied):
> pym/_emerge/depgraph.py(2143)_add_dep()
-> self._dynamic_config._unsatisfied_deps_for_display.append(