Build: fix cmake warning: inconsistent name for if-endif.

CMakeLists.txt

@@ -335,7 +335,7 @@ IF ( ASSIMP_BUILD_ASSIMP_TOOLS )
     IF ( ASSIMP_BUILD_ASSIMP_VIEW )
       ADD_SUBDIRECTORY( tools/assimp_view/ )
     ENDIF ( ASSIMP_BUILD_ASSIMP_VIEW )
-  ENDIF ( WIN32 )
+  ENDIF ( WIN32 AND DirectX_D3DX9_LIBRARY )
 
   ADD_SUBDIRECTORY( tools/assimp_cmd/ )