Apply fix includes.

Cherry-picked from prusa3d/PrusaSlicer@919740fb3e

Co-authored-by: Martin Šach <martin.sachin@gmail.com>

src/libslic3r/Geometry/MedialAxis.cpp

@@ -1,9 +1,16 @@
 #include <boost/log/trivial.hpp>
 #include "MedialAxis.hpp"
 
-#include "clipper.hpp"
+#include <boost/log/trivial.hpp>
+#include <boost/polygon/polygon.hpp>
+#include <cassert>
+#include <cmath>
+
 #include "VoronoiOffset.hpp"
-#include "../ClipperUtils.hpp"
+#include "libslic3r/ClipperUtils.hpp"
+#include "libslic3r/ExPolygon.hpp"
+#include "libslic3r/Point.hpp"
+#include "libslic3r/libslic3r.h"
 
 #ifdef SLIC3R_DEBUG
 namespace boost { namespace polygon {