[libsigc++2/variadic] C++14: compose: Remove use of deduce_result_type.

[Murray Cumming <murrayc src gnome org>]

commit 2aced1af227d9d689449ebebc7a2224ff88a85f7
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Jan 8 11:37:23 2016 +0100

    C++14: compose: Remove use of deduce_result_type.
    
    By removing use of SIGC_WORKAROUND_OPERATOR_PARENTHESES, which
    hopefully isn't necessary any more.

 sigc++/adaptors/compose.h |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)
---
diff --git a/sigc++/adaptors/compose.h b/sigc++/adaptors/compose.h
index ea56eda..2b0a10e 100644
--- a/sigc++/adaptors/compose.h
+++ b/sigc++/adaptors/compose.h
@@ -60,8 +60,7 @@ struct compose1_functor : public adapts<T_setter>
   template <class... T_arg>
   decltype(auto)
   operator()(T_arg... _A_a)
-    { return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<sigc::deduce_result_t<T_getter, T_arg...>>
-        (get_(_A_a...));
+    { return this->functor_(get_(_A_a...));
     }
 
   /** Constructs a compose1_functor object that combines the passed functors.
@@ -114,9 +113,7 @@ struct compose2_functor : public adapts<T_setter>
   template <class... T_arg>
   decltype(auto)
   operator()(T_arg... _A_a)
-    { return this->functor_.SIGC_WORKAROUND_OPERATOR_PARENTHESES<sigc::deduce_result_t<T_getter1, T_arg...>,
-                                                         sigc::deduce_result_t<T_getter2, T_arg...>>
-        (get1_(_A_a...), get2_(_A_a...));
+    { return this->functor_(get1_(_A_a...), get2_(_A_a...));
     }
 
   /** Constructs a compose2_functor object that combines the passed functors.