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

pym/_emerge/resolver/backtracking.py

Index: pym/_emerge/resolver/backtracking.py
diff --git a/pym/_emerge/resolver/backtracking.py b/pym/_emerge/resolver/backtracking.py
index 1ffada96f18fb647253e1377d35a131a8683ffc0..f00e6ca194aeab9e1df8e5368562e266a9209728 100644
--- a/pym/_emerge/resolver/backtracking.py
+++ b/pym/_emerge/resolver/backtracking.py
@@ -7,6 +7,7 @@ class BacktrackParameter(object):
 
 	__slots__ = (
 		"needed_unstable_keywords", "runtime_pkg_mask", "needed_use_config_changes", "needed_license_changes",
+		"rebuild_list", "reinstall_list"
 	)
 
 	def __init__(self):
@@ -14,6 +15,8 @@ class BacktrackParameter(object):
 		self.runtime_pkg_mask = {}
 		self.needed_use_config_changes = {}
 		self.needed_license_changes = {}
+		self.rebuild_list = set()
+		self.reinstall_list = set()
 
 	def __deepcopy__(self, memo=None):
 		if memo is None:
@@ -27,6 +30,8 @@ class BacktrackParameter(object):
 		result.runtime_pkg_mask = copy.copy(self.runtime_pkg_mask)
 		result.needed_use_config_changes = copy.copy(self.needed_use_config_changes)
 		result.needed_license_changes = copy.copy(self.needed_license_changes)
+		result.rebuild_list = copy.copy(self.rebuild_list)
+		result.reinstall_list = copy.copy(self.reinstall_list)
 
 		return result
 
@@ -34,7 +39,9 @@ class BacktrackParameter(object):
 		return self.needed_unstable_keywords == other.needed_unstable_keywords and \
 			self.runtime_pkg_mask == other.runtime_pkg_mask and \
 			self.needed_use_config_changes == other.needed_use_config_changes and \
-			self.needed_license_changes == other.needed_license_changes
+			self.needed_license_changes == other.needed_license_changes and \
+			self.rebuild_list == other.rebuild_list and \
+			self.reinstall_list == other.reinstall_list
 
 
 class _BacktrackNode:
@@ -137,6 +144,10 @@ class Backtracker(object):
 			elif change == "needed_use_config_changes":
 				for pkg, (new_use, new_changes) in data:
 					para.needed_use_config_changes[pkg] = (new_use, new_changes)
+			elif change == "rebuild_list":
+				para.rebuild_list.update(data)
+			elif change == "reinstall_list":
+				para.reinstall_list.update(data)
 
 		self._add(new_node, explore=explore)
 		self._current_node = new_node