first implementation, but for overhangs the code is not run for some reason

src/libslic3r/GCode.hpp

@@ -1,6 +1,7 @@
 #ifndef slic3r_GCode_hpp_
 #define slic3r_GCode_hpp_
 
+#include "GCode/OverhangProcessor.hpp"
 #include "JumpPointSearch.hpp"
 #include "libslic3r.h"
 #include "ExPolygon.hpp"
@@ -332,6 +333,8 @@ private:
 
     // Cache for custom seam enforcers/blockers for each layer.
     SeamPlacer                          m_seam_placer;
+    
+    AABBTreeLines::LinesDistancer<Linef>m_prev_layer_boundary;
 
     /* Origin of print coordinates expressed in unscaled G-code coordinates.
        This affects the input arguments supplied to the extrude*() and travel_to()