diff -ruN boost_1_46_0/boost/thread/detail/thread.hpp boost_1_46_0.new/boost/thread/detail/thread.hpp
--- boost_1_46_0/boost/thread/detail/thread.hpp	2010-08-25 09:41:08.000000000 -0700
+++ boost_1_46_0.new/boost/thread/detail/thread.hpp	2011-06-16 13:18:40.294285390 -0700
@@ -400,6 +400,10 @@
         id():
             thread_data()
         {}
+
+        id(const id& other):
+            thread_data(other.thread_data)
+        {}
             
         bool operator==(const id& y) const
         {