- 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
The two given versions of mariadb are not fetchable under the given
URL, probably because older versions are purged and only kept in
an archive.
Add two working, latest revisions of each release line.
