Build failure on MacOS High Sierra

When building with cmake on MacOS with latest Xcode and OS:

[43%] Building CXX object libshiboken/CMakeFiles/libshiboken.dir/sbkarrayconverter.cpp.o
/Users/build/pyside2/pyside-setup/sources/shiboken2/libshiboken/sbkarrayconverter.cpp:165:29: error:
use of undeclared identifier '_PyLong_AsInt'
convertPySequence(pyIn, _PyLong_AsInt, handle->data());

A possible patch:

 - convertPySequence(pyIn, _PyLong_AsInt, handle->data());
+ convertPySequence(pyIn, PyInt_AsLong, handle->data());