[libsigcplusplus/variadic_mem_fun3: 54/148] make_slot: Use decltype(auto) for return type.

[Murray Cumming <murrayc src gnome org>]

commit 440018b4c0ab41b009d6032315e63d278c837176
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Jan 14 19:41:23 2016 +0100

    make_slot: Use decltype(auto) for return type.

 sigc++/signal.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/sigc++/signal.h b/sigc++/signal.h
index 6f0f130..cfede6f 100644
--- a/sigc++/signal.h
+++ b/sigc++/signal.h
@@ -948,7 +948,7 @@ public:
    * yields the same result.
    * @return A functor that calls emit() on this signal.
    */
-  bound_const_mem_functor<result_type, signal_with_accumulator, type_trait_take_t<T_arg>...> make_slot() 
const
+  decltype(auto) make_slot() const
     { return bound_const_mem_functor<result_type, signal_with_accumulator, 
type_trait_take_t<T_arg>...>(this, &signal_with_accumulator::emit); }
 
   /** Creates an STL-style interface for the signal's list of slots.