Add missing include in helpers.h

Author: LeoValque

Convex_hull_3/doc/Convex_hull_3/PackageDescription.txt

@@ -80,7 +80,7 @@ defining `CGAL_CHECK_EXPENSIVE`.
 \cgalCRPSection{Convex Hull Functions}
 
 - `CGAL::convex_hull_3()`
-- `CGAL::Convex_hull_3::extreme_point_3()`
+- `CGAL::extreme_point_3()`
 - `CGAL::extreme_points_3()`
 - `CGAL::make_extreme_points_traits_adapter()`
 

Convex_hull_3/include/CGAL/Convex_hull_3/distance.h

@@ -28,8 +28,6 @@
 #include <CGAL/Convex_hull_3/internal/helpers.h>
 #include <CGAL/squared_distance_3.h>
 
-#include <CGAL/IO/helpers.h>
-
 #include <CGAL/Container_helper.h>
 #include <CGAL/Dynamic_property_map.h>
 #include <CGAL/property_map.h>

Convex_hull_3/include/CGAL/Convex_hull_3/do_intersect.h

@@ -24,7 +24,6 @@
 #include <CGAL/Convex_hull_hierarchy.h>
 #include <CGAL/intersections.h>
 
-#include <CGAL/IO/helpers.h>
 #include <CGAL/Convex_hull_3/internal/helpers.h>
 
 #include <CGAL/Container_helper.h>

Convex_hull_3/include/CGAL/Convex_hull_3/internal/helpers.h

@@ -14,6 +14,7 @@
 #ifndef CGAL_CONVEX_HULL_INTERNAL_HELPERS_H
 #define CGAL_CONVEX_HULL_INTERNAL_HELPERS_H
 
+#include <CGAL/IO/helpers.h>
 #include <CGAL/license/Convex_hull_3.h>
 
 #ifdef CGAL_PROFILE_CONVEX_HULL_DO_INTERSECT