diff --git a/src/OrcaSlicer.cpp b/src/OrcaSlicer.cpp
index c305f13bb8..e5a8407185 100644
--- a/src/OrcaSlicer.cpp
+++ b/src/OrcaSlicer.cpp
@@ -48,6 +48,7 @@ using namespace nlohmann;
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/Config.hpp"
 #include "libslic3r/Geometry.hpp"
+#include "libslic3r/GCode.hpp"
 #include "libslic3r/GCode/PostProcessor.hpp"
 #include "libslic3r/Model.hpp"
 #include "libslic3r/ModelArrange.hpp"
diff --git a/src/dev-utils/OrcaSlicer_profile_validator.cpp b/src/dev-utils/OrcaSlicer_profile_validator.cpp
index d51af8bba4..f92b14637c 100644
--- a/src/dev-utils/OrcaSlicer_profile_validator.cpp
+++ b/src/dev-utils/OrcaSlicer_profile_validator.cpp
@@ -1,3 +1,4 @@
+#include "libslic3r/GCode.hpp"
 #include "libslic3r/Preset.hpp"
 #include "libslic3r/Config.hpp"
 #include "libslic3r/PresetBundle.hpp"
diff --git a/src/libslic3r/Feature/Interlocking/InterlockingGenerator.cpp b/src/libslic3r/Feature/Interlocking/InterlockingGenerator.cpp
index 64da6aef29..df337f0193 100644
--- a/src/libslic3r/Feature/Interlocking/InterlockingGenerator.cpp
+++ b/src/libslic3r/Feature/Interlocking/InterlockingGenerator.cpp
@@ -2,6 +2,7 @@
 // CuraEngine is released under the terms of the AGPLv3 or higher.
 
 #include "InterlockingGenerator.hpp"
+#include "Layer.hpp"
 
 namespace std {
 template<> struct hash<Slic3r::GridPoint3>
diff --git a/src/libslic3r/Fill/Fill.cpp b/src/libslic3r/Fill/Fill.cpp
index e8294ea673..c953e242b3 100644
--- a/src/libslic3r/Fill/Fill.cpp
+++ b/src/libslic3r/Fill/Fill.cpp
@@ -9,6 +9,7 @@
 #include "../PrintConfig.hpp"
 #include "../Surface.hpp"
 
+#include "AABBTreeLines.hpp"
 #include "ExtrusionEntity.hpp"
 #include "FillBase.hpp"
 #include "FillRectilinear.hpp"
diff --git a/src/libslic3r/Print.hpp b/src/libslic3r/Print.hpp
index 47902e109f..5395dc1d9f 100644
--- a/src/libslic3r/Print.hpp
+++ b/src/libslic3r/Print.hpp
@@ -1,9 +1,9 @@
 #ifndef slic3r_Print_hpp_
 #define slic3r_Print_hpp_
 
+#include "PrintBase.hpp"
 #include "Fill/FillAdaptive.hpp"
 #include "Fill/FillLightning.hpp"
-#include "PrintBase.hpp"
 
 #include "BoundingBox.hpp"
 #include "ExtrusionEntityCollection.hpp"
diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index e1555013c0..8a97858f14 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -20,6 +20,7 @@
 #include "Fill/FillLightning.hpp"
 #include "Format/STL.hpp"
 #include "format.hpp"
+#include "AABBTreeLines.hpp"
 
 #include <float.h>
 #include <oneapi/tbb/blocked_range.h>
diff --git a/src/libslic3r/calib.cpp b/src/libslic3r/calib.cpp
index 4b120ff8d3..1a0c1e04ed 100644
--- a/src/libslic3r/calib.cpp
+++ b/src/libslic3r/calib.cpp
@@ -2,6 +2,7 @@
 #include "BoundingBox.hpp"
 #include "Config.hpp"
 #include "Model.hpp"
+#include "GCode.hpp"
 #include <cmath>
 
 namespace Slic3r {
@@ -755,6 +756,16 @@ Vec3d CalibPressureAdvancePattern::get_start_offset()
     return m_starting_point;
 }
 
+double CalibPressureAdvancePattern::line_width() const
+{
+    // TODO: FIXME: find out current filament/extruder?
+    const double nozzle_diameter = m_config.opt_float("nozzle_diameter", 0);
+    const double width           = m_config.get_abs_value("line_width", nozzle_diameter);
+    if (width <= 0.)
+        return Flow::auto_extrusion_width(frExternalPerimeter, nozzle_diameter);
+    return width;
+};
+
 void CalibPressureAdvancePattern::refresh_setup(const DynamicPrintConfig &config,
                                                 bool                      is_bbl_machine,
                                                 const ModelObject         &object,
diff --git a/src/libslic3r/calib.hpp b/src/libslic3r/calib.hpp
index 18760b945a..a887d17478 100644
--- a/src/libslic3r/calib.hpp
+++ b/src/libslic3r/calib.hpp
@@ -2,10 +2,10 @@
 #include <string>
 #define calib_pressure_advance_dd
 
-#include "GCode.hpp"
 #include "GCodeWriter.hpp"
 #include "PrintConfig.hpp"
 #include "BoundingBox.hpp"
+#include "CustomGCode.hpp"
 
 namespace Slic3r {
 
@@ -319,14 +319,7 @@ protected:
         const double nozzle_diameter = m_config.opt_float("nozzle_diameter", 0);
         return m_config.get_abs_value("initial_layer_line_width", nozzle_diameter);
     };
-    double line_width() const
-    {
-        // TODO: FIXME: find out current filament/extruder?
-        const double nozzle_diameter = m_config.opt_float("nozzle_diameter", 0);
-        const double width = m_config.get_abs_value("line_width", nozzle_diameter);
-        if (width <= 0.) return Flow::auto_extrusion_width(frExternalPerimeter, nozzle_diameter);
-        return width;
-    };
+    double line_width() const;
     int    wall_count() const { return m_config.option<ConfigOptionInt>("wall_loops")->value; };
 
 private: