PR libstdc++/70607 revert recent changes to <tr1/complex>

	PR libstdc++/70607
	* include/tr1/complex (conj): Remove using-declaration and restore
	overloads, reverting previous change.

From-SVN: r244951

libstdc++-v3/ChangeLog

 2017-01-26  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/70607
+	* include/tr1/complex (conj): Remove using-declaration and restore
+	overloads, reverting previous change.
+
 	* testsuite/23_containers/list/operations/78389.cc: Fix for C++11
 	mode.
 	* testsuite/23_containers/priority_queue/requirements/constructible.cc:

libstdc++-v3/include/tr1/complex

@@ -371,7 +371,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     }
 
   using std::arg;
-  using std::conj;
+
+  template<typename _Tp>
+    inline std::complex<_Tp>
+    conj(const std::complex<_Tp>& __z)
+    { return std::conj(__z); }
+
+  template<typename _Tp>
+    inline std::complex<typename __gnu_cxx::__promote<_Tp>::__type>
+    conj(_Tp __x)
+    { return __x; }
+
   using std::imag;
   using std::norm;
   using std::polar;