- [x] add `concretize.lp`, `spack.yaml`, etc. to licensed files
- [x] update all licensed files to say 2013-2021 using
`spack license update-copyright-year`
- [x] appease mypy with some additions to package.py that needed
for oneapi.py
- 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
* glvis@3.3: new package
* mesa-glu: now provides 'glu' (GL Utility library)
* openglu: add package, provides glu
* [GLVis] Use MakefilePackage as base. Add 'develop' version.
Small tweaks in the makefile arguments.
* [GLVis] Locate the X11, GL and GLU libraries within their respective
prefixes. Set the C compiler in the makefile arguments.
* [GLVis] Fix a bug: the same variable was used for two different things.
* [libx11] Add the libs property
* [OpenGL] Add the libs property
* [OpenGLU] Add the libs property
* [GLVis] Use the libs properties of libx11, opengl, and openglu
