Code fixes so that the boostify script works.

asio/include/asio/detail/handler_tracking.hpp

diff --git a/asio/include/asio/detail/handler_tracking.hpp b/asio/include/asio/detail/handler_tracking.hpp
index bc5d5b8..4b81a8e 100644
--- a/asio/include/asio/detail/handler_tracking.hpp
+++ b/asio/include/asio/detail/handler_tracking.hpp
@@ -17,7 +17,11 @@
 
 #include "asio/detail/config.hpp"
 
-namespace asio { class execution_context; }
+namespace asio {
+
+class execution_context;
+
+} // namespace asio
 
 #if defined(ASIO_CUSTOM_HANDLER_TRACKING)
 # include ASIO_CUSTOM_HANDLER_TRACKING

asio/include/asio/detail/thread_group.hpp

diff --git a/asio/include/asio/detail/thread_group.hpp b/asio/include/asio/detail/thread_group.hpp
index 6ae7ebf..be035b9 100644
--- a/asio/include/asio/detail/thread_group.hpp
+++ b/asio/include/asio/detail/thread_group.hpp
@@ -75,7 +75,7 @@
     {
     }
 
-    thread thread_;
+    asio::detail::thread thread_;
     item* next_;
   };