add c14 details in std::c14

- to use already a few c14 convenience details :

-> polymorphic std::plus, e.g.
   boost::mpi::reduce (world, A,C, std::c14::plus<>(),0);
this plus determine the type by itself ...
  -> errors on the type can be very cryptic on the gf.

-> add std::c14::make_unique
(equivalent of make_shared for unique_ptr).

test/triqs/arrays/array_mpi.cpp

@@ -24,6 +24,7 @@
 #include <boost/mpi.hpp>
 #include <iostream>
 #include <sstream>
+#include <triqs/utility/c14.hpp>
 
 using std::cout; using std::endl;
 using namespace triqs::arrays;
@@ -43,7 +44,7 @@ int main(int argc, char* argv[])
 
  if (world.rank() ==0) std::cout<<" A = "<<A<<std::endl;
 
- boost::mpi::reduce (world, A,C, std::plus<array<long,2> >(),0);
+ boost::mpi::reduce (world, A,C, std::c14::plus<>(),0);
 
  int s= world.size();
  if (world.rank() ==0) std::cout<<" C = "<<C<< "  should be "<< array<long,2>( (s*(s+1)/2) * A) <<std::endl;

triqs/utility/c14.hpp

@@ -0,0 +1,47 @@
+/*******************************************************************************
+ *
+ * TRIQS: a Toolbox for Research in Interacting Quantum Systems
+ *
+ * Copyright (C) 2011 by O. Parcollet
+ *
+ * TRIQS is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * TRIQS. If not, see <http://www.gnu.org/licenses/>.
+ *
+ ******************************************************************************/
+#ifndef TRIQS_C14_FIX_H
+#define TRIQS_C14_FIX_H
+#include <memory>
+#include <functional>
+
+// a few that will be C++14, use in advance....
+
+namespace std { 
+ namespace c14 { 
+
+  // use simply std::c14::plus<>() ...
+  template<typename T = void> struct plus: std::plus<T>{};
+
+  template<> struct plus<void> {
+   template<typename T, typename U> 
+    auto operator()( T&& t, U&& u) const DECL_AND_RETURN(std::forward<T>(t) + std::forward<U>(u));
+  };
+
+  template<typename T, typename... Args>
+   std::unique_ptr<T> make_unique(Args&&... args) { return std::unique_ptr<T>(new T(std::forward<Args>(args)...)); }
+
+ }
+}
+
+
+#endif
+