- 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
* Add missing dependencies to gawk
* Fix make check
* Add mawk packages and awk virtual dependency
* Use mawk instead of gawk to build ncurses
* Rearrange order of patches and dependencies
