Attempt to build gr-customModule on windows using msys2

Hello All,

I've attempted to build gr-customModule (Creating Python OOT with
gr-modtool - GNU Radio) on windows using msys2 and I get a build
error. When I complete the build on a linux system, I get the
following __init__.py file.

#
# Copyright 2008,2009 Free Software Foundation, Inc.
#
# SPDX-License-Identifier: GPL-3.0-or-later
#

# The presence of this file turns this directory into a Python package

'''
This is the GNU Radio CUSTOMMODULE module. Place your Python package
description here (python/__init__.py).
'''
import os

# import pybind11 generated symbols into the customModule namespace
try:
# this might fail if the module is python-only
from .customModule_python import *
except ModuleNotFoundError:
pass

# import any pure python here
from .addSubSelect import addSubSelect
#

When I build on windows I get the same __init__.py file minus the
"from .addSubSelect import addSubSelect" line. I've spent the morning
looking through the cmake files to see why I don't get this line, but
am none the wiser. Does anyone know what I am missing on the windows
side to get this line added?

Thanks in advance,

Chris