Clipper: Use std::function for Z fill callback

thirdparty/clipper/clipper.cpp

@@ -2763,7 +2763,7 @@ void Clipper::SetZ( IntPoint& pt, TEdge& e1, TEdge& e2 )
     else if( pt == e2.Top )
         pt.Z = e2.Top.Z;
     else
-        (*m_ZFill)( e1.Bot, e1.Top, e2.Bot, e2.Top, pt );
+        m_ZFill( e1.Bot, e1.Top, e2.Bot, e2.Top, pt );
 }
 
 

thirdparty/clipper/clipper.hpp

@@ -49,6 +49,7 @@
 // use_deprecated: Enables temporary support for the obsolete functions
 // #define use_deprecated
 
+#include <functional>
 #include <vector>
 #include <list>
 #include <set>
@@ -142,8 +143,8 @@ struct DoublePoint
 // ------------------------------------------------------------------------------
 
 #ifdef use_xyz
-typedef void (* ZFillCallback)( IntPoint& e1bot, IntPoint& e1top, IntPoint& e2bot, IntPoint& e2top,
-        IntPoint& pt );
+typedef std::function<void( IntPoint& e1bot, IntPoint& e1top, IntPoint& e2bot, IntPoint& e2top,
+                            IntPoint& pt )> ZFillCallback;
 #endif
 
 enum InitOptions