- 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
- Added a new interface for Specs to pass build information
- Calls forwarded from Spec to Package are now explicit
- Added descriptor within Spec to manage forwarding
- Added state in Spec to maintain query information
- Modified a few packages (the one involved in spack install pexsi) to showcase changes
- This uses an object wrapper to `spec` to implement the `libs` sub-calls.
- wrapper is returned from `__getitem__` only if spec is concrete
- allows packagers to access build information easily
* Turned <provider>_libs into an iterable
Modifications :
- added class LibraryList + unit tests
- added convenience functions `find_libraries` and `dedupe`
- modifed non Intel blas/lapack providers
- modified packages using blas_shared_libs and similar functions
* atlas : added pthread variant
* intel packages : added lapack_libs and blas_libs
* find_library_path : removed unused function
* PR review : fixed last issues
* LibraryList : added test on __add__ return type
* LibraryList : added __radd__ fixed unit tests
fix : failing unit tests due to missing `self`
* cp2k and dependecies : fixed blas-lapack related statements in package.py
