Rebuild when build-time/run-time deps are upgraded.

pym/_emerge/DepPriorityNormalRange.py

 # Copyright 1999-2009 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 from _emerge.DepPriority import DepPriority
 class DepPriorityNormalRange(object):
         """
         DepPriority properties              Index      Category
 
         buildtime                                      HARD
         runtime                                3       MEDIUM
@@ skipping 15 matching lines @@
         @classmethod
         def _ignore_runtime_post(cls, priority):
                 if priority.__class__ is not DepPriority:
                         return False
                 return bool(priority.optional or priority.runtime_post)
 
         @classmethod
         def _ignore_runtime(cls, priority):
                 if priority.__class__ is not DepPriority:
                         return False
-                return not priority.buildtime
+                return bool(priority.optional or not priority.buildtime)
 
         ignore_medium      = _ignore_runtime
         ignore_medium_soft = _ignore_runtime_post
         ignore_soft        = _ignore_optional
 
 DepPriorityNormalRange.ignore_priority = (
         None,
         DepPriorityNormalRange._ignore_optional,
         DepPriorityNormalRange._ignore_runtime_post,
         DepPriorityNormalRange._ignore_runtime
 )