[libsigcplusplus] signal: Use the slot<R(Args...)> syntax.

[Murray Cumming <murrayc src gnome org>]

commit 4ab96d90eff8df1a00b5fd78135b5ed7d69a9da0
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Mar 16 10:29:00 2016 +0100

    signal: Use the slot<R(Args...)> syntax.

 sigc++/signal.h |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/sigc++/signal.h b/sigc++/signal.h
index 0961920..ff72d86 100644
--- a/sigc++/signal.h
+++ b/sigc++/signal.h
@@ -599,7 +599,7 @@ struct signal_emit
 {
   using self_type = signal_emit<T_return, T_accumulator, T_arg...>;
   using result_type = typename T_accumulator::result_type;
-  using slot_type = slot<T_return, T_arg...>;
+  using slot_type = slot<T_return(T_arg...)>;
   using slot_iterator_buf_type = internal::slot_iterator_buf<self_type, T_return>;
   using slot_reverse_iterator_buf_type = internal::slot_reverse_iterator_buf<self_type, T_return>;
   using iterator_type = signal_impl::const_iterator_type;
@@ -683,7 +683,7 @@ struct signal_emit<T_return, void, T_arg...>
 {
   using self_type = signal_emit<T_return, void, T_arg...>;
   using result_type = T_return;
-  using slot_type = slot<T_return, T_arg...>;
+  using slot_type = slot<T_return(T_arg...)>;
   using iterator_type = signal_impl::const_iterator_type;
   using call_type = typename slot_type::call_type;
 
@@ -774,7 +774,7 @@ struct signal_emit<void, void, T_arg...>
 {
   using self_type = signal_emit<void, void, T_arg...>;
   using result_type = void;
-  using slot_type = slot<void, T_arg...>;
+  using slot_type = slot<void(T_arg...)>;
   using iterator_type = signal_impl::const_iterator_type;
   using call_type = typename slot_type::call_type;
 
@@ -854,7 +854,7 @@ class signal_with_accumulator
 public:
   using emitter_type = internal::signal_emit<T_return, T_accumulator, T_arg...>;
   using result_type = typename emitter_type::result_type;
-  using slot_type = slot<T_return, T_arg...>;
+  using slot_type = slot<T_return(T_arg...)>;
   using slot_list_type = slot_list<slot_type>;
   using iterator = typename slot_list_type::iterator;
   using const_iterator = typename slot_list_type::const_iterator;