diff --git a/Advancing_front_surface_reconstruction/package_info/Advancing_front_surface_reconstruction/dependencies b/Advancing_front_surface_reconstruction/package_info/Advancing_front_surface_reconstruction/dependencies
index 80d674f254a..fffe4db3c74 100644
--- a/Advancing_front_surface_reconstruction/package_info/Advancing_front_surface_reconstruction/dependencies
+++ b/Advancing_front_surface_reconstruction/package_info/Advancing_front_surface_reconstruction/dependencies
@@ -19,7 +19,6 @@ Kernel_d
 Modifier
 Modular_arithmetic
 Number_types
-Polygon
 Polyhedron
 Profiling_tools
 Property_map
diff --git a/Alpha_shapes_3/package_info/Alpha_shapes_3/dependencies b/Alpha_shapes_3/package_info/Alpha_shapes_3/dependencies
index 6a453cfa1e9..f0dc76c90d9 100644
--- a/Alpha_shapes_3/package_info/Alpha_shapes_3/dependencies
+++ b/Alpha_shapes_3/package_info/Alpha_shapes_3/dependencies
@@ -11,7 +11,6 @@ Interval_support
 Kernel_23
 Modular_arithmetic
 Number_types
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Apollonius_graph_2/package_info/Apollonius_graph_2/dependencies b/Apollonius_graph_2/package_info/Apollonius_graph_2/dependencies
index 326f1dd8070..d0ac5f0a017 100644
--- a/Apollonius_graph_2/package_info/Apollonius_graph_2/dependencies
+++ b/Apollonius_graph_2/package_info/Apollonius_graph_2/dependencies
@@ -14,7 +14,6 @@ Interval_support
 Kernel_23
 Modular_arithmetic
 Number_types
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Hyperbolic_triangulation_2/package_info/Hyperbolic_triangulation_2/dependencies b/Hyperbolic_triangulation_2/package_info/Hyperbolic_triangulation_2/dependencies
index 72b10e709ef..a0d8892a1d5 100644
--- a/Hyperbolic_triangulation_2/package_info/Hyperbolic_triangulation_2/dependencies
+++ b/Hyperbolic_triangulation_2/package_info/Hyperbolic_triangulation_2/dependencies
@@ -19,7 +19,6 @@ Kernel_23
 Kernel_d
 Modular_arithmetic
 Number_types
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Interpolation/include/CGAL/regular_neighbor_coordinates_2.h b/Interpolation/include/CGAL/regular_neighbor_coordinates_2.h
index 7fbb978bf8c..ce5c62c0b76 100644
--- a/Interpolation/include/CGAL/regular_neighbor_coordinates_2.h
+++ b/Interpolation/include/CGAL/regular_neighbor_coordinates_2.h
@@ -20,6 +20,7 @@
 #include <CGAL/iterator.h>
 #include <CGAL/utility.h>
 #include <CGAL/function_objects.h>
+#include <CGAL/Polygon_2_algorithms.h>
 
 #include <boost/utility/enable_if.hpp>
 #include <boost/type_traits/is_convertible.hpp>
diff --git a/Mesh_3/package_info/Mesh_3/dependencies b/Mesh_3/package_info/Mesh_3/dependencies
index 2bfb2043f8b..e616acd30b8 100644
--- a/Mesh_3/package_info/Mesh_3/dependencies
+++ b/Mesh_3/package_info/Mesh_3/dependencies
@@ -24,7 +24,6 @@ Mesher_level
 Modifier
 Modular_arithmetic
 Number_types
-Polygon
 Polygon_mesh_processing
 Polyhedron
 Principal_component_analysis
diff --git a/Optimal_transportation_reconstruction_2/package_info/Optimal_transportation_reconstruction_2/dependencies b/Optimal_transportation_reconstruction_2/package_info/Optimal_transportation_reconstruction_2/dependencies
index 7fb921a03fa..1f25a1c4d47 100644
--- a/Optimal_transportation_reconstruction_2/package_info/Optimal_transportation_reconstruction_2/dependencies
+++ b/Optimal_transportation_reconstruction_2/package_info/Optimal_transportation_reconstruction_2/dependencies
@@ -12,7 +12,6 @@ Kernel_23
 Modular_arithmetic
 Number_types
 Optimal_transportation_reconstruction_2
-Polygon
 Profiling_tools
 Property_map
 Random_numbers
diff --git a/Periodic_2_triangulation_2/package_info/Periodic_2_triangulation_2/dependencies b/Periodic_2_triangulation_2/package_info/Periodic_2_triangulation_2/dependencies
index a78447643d8..22f0ba917df 100644
--- a/Periodic_2_triangulation_2/package_info/Periodic_2_triangulation_2/dependencies
+++ b/Periodic_2_triangulation_2/package_info/Periodic_2_triangulation_2/dependencies
@@ -14,7 +14,6 @@ Kernel_23
 Modular_arithmetic
 Number_types
 Periodic_2_triangulation_2
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Periodic_3_mesh_3/package_info/Periodic_3_mesh_3/dependencies b/Periodic_3_mesh_3/package_info/Periodic_3_mesh_3/dependencies
index c07e2af9cd5..7fb9ae91209 100644
--- a/Periodic_3_mesh_3/package_info/Periodic_3_mesh_3/dependencies
+++ b/Periodic_3_mesh_3/package_info/Periodic_3_mesh_3/dependencies
@@ -22,7 +22,6 @@ Modular_arithmetic
 Number_types
 Periodic_3_mesh_3
 Periodic_3_triangulation_3
-Polygon
 Principal_component_analysis
 Principal_component_analysis_LGPL
 Profiling_tools
diff --git a/Periodic_3_triangulation_3/package_info/Periodic_3_triangulation_3/dependencies b/Periodic_3_triangulation_3/package_info/Periodic_3_triangulation_3/dependencies
index ccf19df4283..b31b936ff04 100644
--- a/Periodic_3_triangulation_3/package_info/Periodic_3_triangulation_3/dependencies
+++ b/Periodic_3_triangulation_3/package_info/Periodic_3_triangulation_3/dependencies
@@ -16,7 +16,6 @@ Kernel_d
 Modular_arithmetic
 Number_types
 Periodic_3_triangulation_3
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Periodic_4_hyperbolic_triangulation_2/package_info/Periodic_4_hyperbolic_triangulation_2/dependencies b/Periodic_4_hyperbolic_triangulation_2/package_info/Periodic_4_hyperbolic_triangulation_2/dependencies
index 3c6be77faf7..d4694a4551a 100644
--- a/Periodic_4_hyperbolic_triangulation_2/package_info/Periodic_4_hyperbolic_triangulation_2/dependencies
+++ b/Periodic_4_hyperbolic_triangulation_2/package_info/Periodic_4_hyperbolic_triangulation_2/dependencies
@@ -16,7 +16,6 @@ Kernel_23
 Modular_arithmetic
 Number_types
 Periodic_4_hyperbolic_triangulation_2
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Point_set_2/package_info/Point_set_2/dependencies b/Point_set_2/package_info/Point_set_2/dependencies
index 22b6e1e57b7..72d35397d68 100644
--- a/Point_set_2/package_info/Point_set_2/dependencies
+++ b/Point_set_2/package_info/Point_set_2/dependencies
@@ -8,7 +8,6 @@ Kernel_23
 Modular_arithmetic
 Number_types
 Point_set_2
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Point_set_processing_3/package_info/Point_set_processing_3/dependencies b/Point_set_processing_3/package_info/Point_set_processing_3/dependencies
index 34b36f0b394..dcdadf3e8dc 100644
--- a/Point_set_processing_3/package_info/Point_set_processing_3/dependencies
+++ b/Point_set_processing_3/package_info/Point_set_processing_3/dependencies
@@ -22,7 +22,6 @@ Modular_arithmetic
 Number_types
 Point_set_2
 Point_set_processing_3
-Polygon
 Principal_component_analysis
 Principal_component_analysis_LGPL
 Profiling_tools
diff --git a/Poisson_surface_reconstruction_3/package_info/Poisson_surface_reconstruction_3/dependencies b/Poisson_surface_reconstruction_3/package_info/Poisson_surface_reconstruction_3/dependencies
index 81a3dea3b55..5c532a3d624 100644
--- a/Poisson_surface_reconstruction_3/package_info/Poisson_surface_reconstruction_3/dependencies
+++ b/Poisson_surface_reconstruction_3/package_info/Poisson_surface_reconstruction_3/dependencies
@@ -20,7 +20,6 @@ Modular_arithmetic
 Number_types
 Point_set_processing_3
 Poisson_surface_reconstruction_3
-Polygon
 Principal_component_analysis_LGPL
 Profiling_tools
 Property_map
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Hole_filling/Triangulate_hole_polyline.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Hole_filling/Triangulate_hole_polyline.h
index a28b3e2c826..5eab37058cd 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Hole_filling/Triangulate_hole_polyline.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Hole_filling/Triangulate_hole_polyline.h
@@ -30,6 +30,7 @@
 #include <CGAL/Constrained_Delaunay_triangulation_2.h>
 #include <CGAL/Projection_traits_3.h>
 #include <queue>
+#include <CGAL/Polygon_2_algorithms.h>
 #endif
 
 #include <CGAL/utility.h>
diff --git a/Scale_space_reconstruction_3/package_info/Scale_space_reconstruction_3/dependencies b/Scale_space_reconstruction_3/package_info/Scale_space_reconstruction_3/dependencies
index 3a5c0a7b9e2..114d4ba5acd 100644
--- a/Scale_space_reconstruction_3/package_info/Scale_space_reconstruction_3/dependencies
+++ b/Scale_space_reconstruction_3/package_info/Scale_space_reconstruction_3/dependencies
@@ -22,7 +22,6 @@ Modifier
 Modular_arithmetic
 Number_types
 Point_set_processing_3
-Polygon
 Polyhedron
 Profiling_tools
 Property_map
diff --git a/Segment_Delaunay_graph_2/package_info/Segment_Delaunay_graph_2/dependencies b/Segment_Delaunay_graph_2/package_info/Segment_Delaunay_graph_2/dependencies
index 36deee2c524..c3083729fef 100644
--- a/Segment_Delaunay_graph_2/package_info/Segment_Delaunay_graph_2/dependencies
+++ b/Segment_Delaunay_graph_2/package_info/Segment_Delaunay_graph_2/dependencies
@@ -16,7 +16,6 @@ Kernel_23
 Kernel_d
 Modular_arithmetic
 Number_types
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Skin_surface_3/package_info/Skin_surface_3/dependencies b/Skin_surface_3/package_info/Skin_surface_3/dependencies
index c95013b1fbe..fb635c6334c 100644
--- a/Skin_surface_3/package_info/Skin_surface_3/dependencies
+++ b/Skin_surface_3/package_info/Skin_surface_3/dependencies
@@ -18,7 +18,6 @@ Kernel_d
 Modifier
 Modular_arithmetic
 Number_types
-Polygon
 Polyhedron
 Profiling_tools
 Property_map
diff --git a/Spatial_sorting/include/CGAL/Hilbert_sort_middle_2.h b/Spatial_sorting/include/CGAL/Hilbert_sort_middle_2.h
index 766e4fac4c6..32cf03cc435 100644
--- a/Spatial_sorting/include/CGAL/Hilbert_sort_middle_2.h
+++ b/Spatial_sorting/include/CGAL/Hilbert_sort_middle_2.h
@@ -16,7 +16,7 @@
 #include <functional>
 #include <cstddef>
 #include <CGAL/Hilbert_sort_middle_base.h>
-#include <CGAL/Polygon_2_algorithms.h>
+#include <CGAL/number_utils.h>
 
 namespace CGAL {
 
diff --git a/Spatial_sorting/include/CGAL/hilbert_sort.h b/Spatial_sorting/include/CGAL/hilbert_sort.h
index 97973dd4058..fc6d7bddb8b 100644
--- a/Spatial_sorting/include/CGAL/hilbert_sort.h
+++ b/Spatial_sorting/include/CGAL/hilbert_sort.h
@@ -19,6 +19,7 @@
 #include <CGAL/Hilbert_sort_2.h>
 #include <CGAL/Hilbert_sort_3.h>
 #include <CGAL/Hilbert_sort_d.h>
+#include <CGAL/Kernel_traits.h>
 #include <CGAL/algorithm.h>
 
 #include <boost/random/random_number_generator.hpp>
diff --git a/Spatial_sorting/package_info/Spatial_sorting/dependencies b/Spatial_sorting/package_info/Spatial_sorting/dependencies
index ca434381fc1..7fb348192a7 100644
--- a/Spatial_sorting/package_info/Spatial_sorting/dependencies
+++ b/Spatial_sorting/package_info/Spatial_sorting/dependencies
@@ -2,7 +2,6 @@ Algebraic_foundations
 Installation
 Kernel_23
 Number_types
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Surface_mesh_parameterization/package_info/Surface_mesh_parameterization/dependencies b/Surface_mesh_parameterization/package_info/Surface_mesh_parameterization/dependencies
index d66c39f593f..6dedee5435a 100644
--- a/Surface_mesh_parameterization/package_info/Surface_mesh_parameterization/dependencies
+++ b/Surface_mesh_parameterization/package_info/Surface_mesh_parameterization/dependencies
@@ -15,7 +15,6 @@ Kernel_23
 Modular_arithmetic
 Number_types
 OpenNL
-Polygon
 Polygon_mesh_processing
 Profiling_tools
 Property_map
diff --git a/Surface_mesh_skeletonization/package_info/Surface_mesh_skeletonization/dependencies b/Surface_mesh_skeletonization/package_info/Surface_mesh_skeletonization/dependencies
index 27b87718afb..2aacacc3663 100644
--- a/Surface_mesh_skeletonization/package_info/Surface_mesh_skeletonization/dependencies
+++ b/Surface_mesh_skeletonization/package_info/Surface_mesh_skeletonization/dependencies
@@ -20,7 +20,6 @@ Kernel_d
 Modifier
 Modular_arithmetic
 Number_types
-Polygon
 Polygon_mesh_processing
 Polyhedron
 Profiling_tools
diff --git a/Surface_mesher/package_info/Surface_mesher/dependencies b/Surface_mesher/package_info/Surface_mesher/dependencies
index 23de87a5e19..e6e8a390966 100644
--- a/Surface_mesher/package_info/Surface_mesher/dependencies
+++ b/Surface_mesher/package_info/Surface_mesher/dependencies
@@ -21,7 +21,6 @@ Mesher_level
 Modifier
 Modular_arithmetic
 Number_types
-Polygon
 Polyhedron
 Profiling_tools
 Property_map
diff --git a/Tetrahedral_remeshing/package_info/Tetrahedral_remeshing/dependencies b/Tetrahedral_remeshing/package_info/Tetrahedral_remeshing/dependencies
index 2311653695c..57bd26ce97b 100644
--- a/Tetrahedral_remeshing/package_info/Tetrahedral_remeshing/dependencies
+++ b/Tetrahedral_remeshing/package_info/Tetrahedral_remeshing/dependencies
@@ -17,7 +17,6 @@ Kernel_d
 Mesh_3
 Modular_arithmetic
 Number_types
-Polygon
 Polygon_mesh_processing
 Profiling_tools
 Property_map
diff --git a/Triangulation/package_info/Triangulation/dependencies b/Triangulation/package_info/Triangulation/dependencies
index f26faea33f6..c7893bd09b0 100644
--- a/Triangulation/package_info/Triangulation/dependencies
+++ b/Triangulation/package_info/Triangulation/dependencies
@@ -5,7 +5,6 @@ Interval_support
 Kernel_23
 Modular_arithmetic
 Number_types
-Polygon
 Profiling_tools
 Random_numbers
 STL_Extension
diff --git a/Triangulation_3/package_info/Triangulation_3/dependencies b/Triangulation_3/package_info/Triangulation_3/dependencies
index 53da26a4122..a68982ddaa5 100644
--- a/Triangulation_3/package_info/Triangulation_3/dependencies
+++ b/Triangulation_3/package_info/Triangulation_3/dependencies
@@ -17,7 +17,6 @@ Kernel_23
 Kernel_d
 Modular_arithmetic
 Number_types
-Polygon
 Profiling_tools
 Property_map
 Random_numbers
diff --git a/Triangulation_on_sphere_2/package_info/Triangulation_on_sphere_2/dependencies b/Triangulation_on_sphere_2/package_info/Triangulation_on_sphere_2/dependencies
index d0187657dfe..5b77a741e4d 100644
--- a/Triangulation_on_sphere_2/package_info/Triangulation_on_sphere_2/dependencies
+++ b/Triangulation_on_sphere_2/package_info/Triangulation_on_sphere_2/dependencies
@@ -16,7 +16,6 @@ Interval_support
 Kernel_23
 Modular_arithmetic
 Number_types
-Polygon
 Profiling_tools
 Property_map
 STL_Extension
diff --git a/Visibility_2/package_info/Visibility_2/dependencies b/Visibility_2/package_info/Visibility_2/dependencies
index bdaf92f883b..7acbd250303 100644
--- a/Visibility_2/package_info/Visibility_2/dependencies
+++ b/Visibility_2/package_info/Visibility_2/dependencies
@@ -13,7 +13,6 @@ Interval_support
 Kernel_23
 Modular_arithmetic
 Number_types
-Polygon
 Principal_component_analysis_LGPL
 Profiling_tools
 Property_map