Merge branch 'master' into jgrpp

# Conflicts:
#	src/company_cmd.cpp
#	src/core/geometry_func.cpp
#	src/date.cpp
#	src/genworld_gui.cpp
#	src/gfx.cpp
#	src/object_gui.cpp
#	src/openttd.cpp
#	src/settings_type.h
#	src/video/allegro_v.cpp
#	src/video/dedicated_v.cpp
#	src/video/null_v.cpp
#	src/video/sdl2_v.cpp
#	src/video/sdl_v.cpp
#	src/video/win32_v.cpp

src/core/geometry_func.hpp

@@ -15,4 +15,16 @@
 Dimension maxdim(const Dimension &d1, const Dimension &d2);
 Dimension adddim(const Dimension &d1, const Dimension &d2);
 
+/**
+ * Check if a rectangle is empty.
+ * @param r Rectangle to check.
+ * @return True if and only if the rectangle doesn't define space.
+ */
+static inline bool IsEmptyRect(const Rect &r)
+{
+	return (r.left | r.top | r.right | r.bottom) == 0;
+}
+
+Rect BoundingRect(const Rect &r1, const Rect &r2);
+
 #endif /* GEOMETRY_FUNC_HPP */