new package ddd (#15717)
new package ddd (#15717)

* new package ddd

* mitigate build/installs on case-insensitive filesystems

* add missing variants

* flake8 fixes

* flake8: E124 closing bracket does not match visual indentation

Co-authored-by: Daryl W. Grunau <58469ba664997fcb401d465b27655a3c41d34e08@lanl.gov>
iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack