try to workaround warnings

Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/Algebraic_curve_kernel_2.h

@@ -357,6 +357,7 @@ public:
          : _inner(inner), _outer(outer) {}
 
        Unary_compose(const Unary_compose& other) = default;
+       Unary_compose& operator=(const Unary_compose& other) = default;
 
        Unary_compose() : _inner(::boost::none),_outer(::boost::none) {}
 

Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/Bitstream_descartes.h

@@ -1148,6 +1148,7 @@ public:
 
   //! Copy constructor
   Bitstream_descartes(const Self& other) = default;
+  Bitstream_descartes& operator=(const Self& other) = default;
 
   /*!
    * \brief Constructor for a polynomial \c f

Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/Bitstream_descartes_E08_tree.h

@@ -467,6 +467,7 @@ private:
         log_C_eps_        = n.log_C_eps_;
     }
 
+    Bitstream_descartes_E08_node(const Self&) = delete;
     Self& operator= (const Self&) = delete;
 }; // struct Bitstream_descartes_E08_node
 

Algebraic_kernel_d/include/CGAL/Algebraic_kernel_d/Bitstream_descartes_rndl_tree.h

@@ -558,6 +558,7 @@ private:
         log_C_eps_     = n.log_C_eps_;
     }
 
+    Bitstream_descartes_rndl_node(const Self&)=delete;
     Self& operator= (const Self&)=delete;
 }; // struct Bitstream_descartes_rndl_node
 

Minkowski_sum_2/include/CGAL/Minkowski_sum_2/AABB_segment_2_primitive.h

@@ -35,7 +35,8 @@ public:
   {
   }
 
-  AABB_segment_2_primitive(const AABB_segment_2_primitive &primitive) = default;
+  AABB_segment_2_primitive(const AABB_segment_2_primitive& primitive) = default;
+  AABB_segment_2_primitive& operator=(const AABB_segment_2_primitive& primitive) = default;
 
   const Id &id() const
   {

Nef_3/include/CGAL/Nef_3/SNC_SM_explorer.h

@@ -30,6 +30,7 @@ class SNC_SM_explorer : public SMCDEC {
 
  public:
   SNC_SM_explorer(const Base& E) : Base(E) {}
+  SNC_SM_explorer(const Self& E) = default;
   Self& operator=(const Self& E) = default;
 };
 

STL_Extension/include/CGAL/iterator.h

@@ -1283,6 +1283,8 @@ template < typename D, typename V = std::tuple<>, typename O = std::tuple<> >
 struct Derivator
 {
   typedef Derivator<D, V, O> Self;
+  Derivator() = default;
+  Derivator(const Self&) = default;
   Self& operator=(const Self&) = delete;
   template <class Tuple>
   void tuple_dispatch(const Tuple&)
@@ -1296,6 +1298,8 @@ struct Derivator<D, std::tuple<V1, V...>, std::tuple<O1, O...> >
   typedef Derivator<D, std::tuple<V1, V...>, std::tuple<O1, O...> > Self;
   typedef Derivator<D, std::tuple<V...>, std::tuple<O...> > Base;
 
+  Derivator() = default;
+  Derivator(const Self&) = default;
   Self& operator=(const Self&) = delete;
 
   using Base::operator=;