Tag to be used with the master branch of atlas/athena.
Update(s) since 2.0.65:
- Moved POST_BUILD_CMD into atlas_install_generic(...), and made it a list type parameter;
* Also updated the handling of ATLAS_PYTHON_CHECKER to deal correctly with list variables;
- Updated flake8_atlas not to fail when no python files are given to it, in case the user makes a mistake that would result in this.