Per discussion in https://discourse.itk.org/t/how-to-build-python-module/5925, update manual build instructions at https://itkpythonpackage.readthedocs.io/en/latest/Build_ITK_Module_Python_packages.html with help on exporting variables to control the build process.
Per discussion in https://discourse.itk.org/t/how-to-build-python-module/5925, update manual build instructions at https://itkpythonpackage.readthedocs.io/en/latest/Build_ITK_Module_Python_packages.html with help on exporting variables to control the build process.