diff --git a/tools/building.py b/tools/building.py
index d9fecd15679c3fdabe52216fc66a88a61129121d..680c6a55ab6648167e2b2a8dbac8bcd10792001a 100644
--- a/tools/building.py
+++ b/tools/building.py
@@ -775,8 +775,16 @@ def DoBuilding(target, objects):
                             objects.remove(obj)
 
         # re-add the source files to the objects
+
+        objects_in_group = []
         for group in Projects:
-            local_group(group, objects)
+            local_group(group, objects_in_group)
+
+        # sort seperately, because the data type of
+        # the members of the two lists are different
+        objects_in_group = sorted(objects_in_group)
+        objects = sorted(objects)
+        objects.append(objects_in_group)
 
         program = Env.Program(target, objects)