d3dx9_36: Implement D3DXComputeBoundingBox.

include/d3dx9.h

diff --git a/include/d3dx9.h b/include/d3dx9.h
index b551eba..6b3bdf6 100644
--- a/include/d3dx9.h
+++ b/include/d3dx9.h
@@ -24,6 +24,7 @@
 #include "d3d9.h"
 #include "d3dx9math.h"
 #include "d3dx9core.h"
+#include "d3dx9mesh.h"
 #include "d3dx9shader.h"
 #include "d3dx9tex.h"