* Add version 11.2.68
* Add variant to disable AVX2 for older hardware
* Change the makefile so libraries and includes are not placed
under $PREFIX/usr
* Updated URL and homepage
- 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