- 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
* fix to build libmatheval with guile@2.0:
* fixed formatting issues
* fixed formatting issues2
* fixed check for autoreconf and renaming of configure.in
* fixed force_autoreconf
* now patching configure, which is hopefully more robust
* minimal patches for guile 2.0 and 2.2 (disabeling unit testing for libmatheval)
* minimal patches for guile 2.0 and 2.2 (disabeling unit testing for libmatheval)
