PyArrayObject redefined in TMVA/PyMethodBase.h with different type

I can successfully build an application using rootcling that also links to python and numpy with ROOT v6.12.06, but since I switched to v6.18.04 the following error appears:

[...]/lib/python2.7/site-packages/numpy-1.15.4-py2.7-linux-x86_64.egg/numpy/core/include/numpy/ndarraytypes.h:719:30: error: typedef redefinition with different types ('PyArrayObject_fields' (aka 'tagPyArrayObject_fields') vs 'tagPyArrayObject')
typedef PyArrayObject_fields PyArrayObject;

[...]/root/v6_18_04b/Linux64bit+2.6-2.12-e17-prof/etc/.../include/TMVA/PyMethodBase.h:50:26: note: previous definition is here
typedef tagPyArrayObject PyArrayObject;

I made a simplified project that reproduces this issue (available here). In this project, a class "ExampleClass" is built, which uses numpy array objects included via

#include "Python.h"

#include "numpy/arrayobject.h"

I also added a simple GNU makefile to build this class, which calls rootcling and then g++ as described here. Once built, the library libMyLib.so is created, then:

root -l

> gROOT->ProcessLine(".L libMyLib.so")

> example::ExampleClass e

This works fine with ROOT v6.12.06, but it returns the above error with v6.18.04. Thank you for considering!