6 files changed, 6 insertions, 0 deletions
diff --git a/src/ui/tool/control-point-selection.h b/src/ui/tool/control-point-selection.h
index a9c929cb1..7e09d50f5 100644
--- a/src/ui/tool/control-point-selection.h
+++ b/src/ui/tool/control-point-selection.h
@@ -14,6 +14,7 @@
 
 #include <memory>
 #include <boost/optional.hpp>
+#include <stddef.h>
 #include <sigc++/sigc++.h>
 #include <2geom/forward.h>
 #include <2geom/point.h>
diff --git a/src/ui/tool/control-point.h b/src/ui/tool/control-point.h
index 0b88786e5..9f62fca42 100644
--- a/src/ui/tool/control-point.h
+++ b/src/ui/tool/control-point.h
@@ -12,6 +12,7 @@
 #define SEEN_UI_TOOL_CONTROL_POINT_H
 
 #include <boost/utility.hpp>
+#include <stddef.h>
 #include <sigc++/sigc++.h>
 #include <gdkmm.h>
 #include <gtkmm.h>
diff --git a/src/ui/tool/manipulator.h b/src/ui/tool/manipulator.h
index fd24e7b61..6866ec9dd 100644
--- a/src/ui/tool/manipulator.h
+++ b/src/ui/tool/manipulator.h
@@ -13,6 +13,7 @@
 
 #include <set>
 #include <map>
+#include <stddef.h>
 #include <sigc++/sigc++.h>
 #include <glib.h>
 #include <gdk/gdk.h>
diff --git a/src/ui/tool/multi-path-manipulator.h b/src/ui/tool/multi-path-manipulator.h
index aef9c1ac9..c25719790 100644
--- a/src/ui/tool/multi-path-manipulator.h
+++ b/src/ui/tool/multi-path-manipulator.h
@@ -11,6 +11,7 @@
 #ifndef SEEN_UI_TOOL_MULTI_PATH_MANIPULATOR_H
 #define SEEN_UI_TOOL_MULTI_PATH_MANIPULATOR_H
 
+#include <stddef.h>
 #include <sigc++/connection.h>
 #include "forward.h"
 #include "ui/tool/commit-events.h"
diff --git a/src/ui/tool/node-tool.h b/src/ui/tool/node-tool.h
index bcf6a8d5e..d005a0bdf 100644
--- a/src/ui/tool/node-tool.h
+++ b/src/ui/tool/node-tool.h
@@ -14,6 +14,7 @@
 #include <memory>
 #include <boost/ptr_container/ptr_map.hpp>
 #include <glib.h>
+#include <stddef.h>
 #include <sigc++/sigc++.h>
 #include "event-context.h"
 #include "forward.h"
diff --git a/src/ui/tool/node.h b/src/ui/tool/node.h
index 451915dbe..b7145790b 100644
--- a/src/ui/tool/node.h
+++ b/src/ui/tool/node.h
@@ -15,6 +15,7 @@
 #include <iterator>
 #include <iosfwd>
 #include <stdexcept>
+#include <cstddef>
 #include <tr1/functional>
 #include <boost/utility.hpp>
 #include <boost/shared_ptr.hpp>