Codechange: rename smallvec_type to container_func and use only when needed

src/gfx_layout.cpp

@@ -8,6 +8,7 @@
 /** @file gfx_layout.cpp Handling of laying out text. */
 
 #include "stdafx.h"
+#include "core/math_func.hpp"
 #include "gfx_layout.h"
 #include "string_func.h"
 #include "debug.h"