We'd like to use a consistent checksum scheme everywhere so that we can:
a) incorporate archive checksums into our specs and have a
consistent hashing algorithm across all specs.
b) index mirrors with a consistent type of checksum, and not one that
is dependent on how spack packages are written.
- [x] convert existing md5, sha224, sha512, sha1 checksums to sha256
- 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
* Turning off default Qt support. Restricting Qt version to <= 4.9 else geant4 won't build
* Making vecgeom optional
* Differentiating between cxx11 and cxx14 support
* Making vecgeom optional. Part 2. forgot to move usolids option
* Adding explicit CXX11 and CXX14 support
* Adding more clhep version to support newer GEANT4 versions
* Adding GEANT4 versions 10.03.p03 and 10.04
* Checkpoint. Adding opengl and x11 variant. Lead up to more changes to enable X11 support
* Adding dependency on fixesproto for newer versions
* Making the X11 dependent pieces work without requiring X11 on the system
* Adding motif
