- remove the old LGPL license headers from all files in Spack
- add SPDX headers to all files
- core and most packages are (Apache-2.0 OR MIT)
- a very small number of remaining packages are LGPL-2.1-only
+ Count, or compute differences of, physical lines of source code in the
given files (may be archives such as compressed tarballs or zip files)
and/or recursively below the given directories.