diff --git a/xs/src/libslic3r/GCode/ToolOrdering.hpp b/xs/src/libslic3r/GCode/ToolOrdering.hpp
index 1a9f1baff..fe2c394c5 100644
--- a/xs/src/libslic3r/GCode/ToolOrdering.hpp
+++ b/xs/src/libslic3r/GCode/ToolOrdering.hpp
@@ -71,7 +71,7 @@ public:
 	const LayerTools&   back()        const { return m_layer_tools.back(); }
 	bool 				empty()       const { return m_layer_tools.empty(); }
 	const std::vector<LayerTools>& layer_tools() const { return m_layer_tools; }
-	bool 				has_wipe_tower() const { return ! m_layer_tools.empty() && m_first_printing_extruder != (size_t)-1 && m_layer_tools.front().wipe_tower_partitions > 0; }
+	bool 				has_wipe_tower() const { return ! m_layer_tools.empty() && m_first_printing_extruder != (unsigned int)-1 && m_layer_tools.front().wipe_tower_partitions > 0; }
 
 private:
 	void				initialize_layers(std::vector<coordf_t> &zs);
@@ -82,9 +82,9 @@ private:
 
 	std::vector<LayerTools> 	m_layer_tools;
 	// First printing extruder, including the multi-material priming sequence.
-	unsigned int 				m_first_printing_extruder;
+	unsigned int 				m_first_printing_extruder = (unsigned int)-1;
 	// Final printing extruder.
-	unsigned int 				m_last_printing_extruder;
+	unsigned int 				m_last_printing_extruder  = (unsigned int)-1;
 	// All extruders, which extrude some material over m_layer_tools.
     std::vector<unsigned int> 	m_all_printing_extruders;
 };
diff --git a/xs/src/libslic3r/libslic3r.h b/xs/src/libslic3r/libslic3r.h
index 4a68b030d..e70113710 100644
--- a/xs/src/libslic3r/libslic3r.h
+++ b/xs/src/libslic3r/libslic3r.h
@@ -92,6 +92,11 @@ inline std::string debug_out_path(const char *name, ...)
 #define UNUSED(x) (void)(x)
 #endif /* UNUSED */
 
+// Detect whether the compiler supports C++11 noexcept exception specifications.
+#if defined(_MSC_VER) && _MSC_VER < 1900
+    #define noexcept throw()
+#endif
+
 // Write slices as SVG images into out directory during the 2D processing of the slices.
 // #define SLIC3R_DEBUG_SLICE_PROCESSING
 
diff --git a/xs/xsp/GCode.xsp b/xs/xsp/GCode.xsp
index ea54fd3a7..2b6809a39 100644
--- a/xs/xsp/GCode.xsp
+++ b/xs/xsp/GCode.xsp
@@ -41,5 +41,5 @@
         %};
 
     Ref<StaticPrintConfig> config()
-        %code{% RETVAL = const_cast<StaticPrintConfig*>(dynamic_cast<const StaticPrintConfig*>(&THIS->config())); %};
+        %code{% RETVAL = const_cast<StaticPrintConfig*>(static_cast<const PrintObjectConfig*>(&THIS->config())); %};
 };