diff --git a/src/libslic3r/Geometry/VoronoiUtilsCgal.cpp b/src/libslic3r/Geometry/VoronoiUtilsCgal.cpp
index 7797a5a29f..28a648851d 100644
--- a/src/libslic3r/Geometry/VoronoiUtilsCgal.cpp
+++ b/src/libslic3r/Geometry/VoronoiUtilsCgal.cpp
@@ -1,3 +1,5 @@
+// Needed since the CGAL headers are not self-contained.
+#include <boost/next_prior.hpp>
 #include <CGAL/Exact_predicates_exact_constructions_kernel.h>
 #include <CGAL/Arr_segment_traits_2.h>
 #include <CGAL/Surface_sweep_2_algorithms.h>