Packaging https://spack.readthedocs.io/en/latest/packaging_guide.html External packages http://spack.readthedocs.io/en/latest/build_settings.html#external-packages https://proxyapps.exascaleproject.org/downloads/ Cray https://github.com/spack/spack/issues/3153 Contribution guide http://spack.readthedocs.io/en/latest/contribution_guide.html Pull request https://github.com/spack/spack/pull/8023 Spack packaging