- 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
* Need to help Makefile.PL find the expat bits
We need to provide Makefile.PL with a clue about where our
expat bits live. We had the dependency, but I suspect
that the lib was actually linking against a system version.
* Use prefix.lib instead of building path myself
Ditto with .include
