Preferred targets were failing because we were looking them up by
Microarchitecture object, not by string.
- [x] Add a call to `str()` to fix target lookup.
- [x] Add a test to exercise this part of concretization.
- [x] Add documentation for setting `target` in `packages.yaml`
Add an example of a 'modules:' entry for an external package in
packages.yaml. The 'External Packages' section of 'Build
Customization' mentions 'paths:' and 'modules:' and gives an
example of paths, but not modules.
- 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
Spack can now be configured to assign permissions to the files installed by a package.
In the `packages.yaml` file under `permissions`, the attributes `read`, `write`, and `group` control the package permissions. These attributes can be set per-package, or for all packages under `all`. If permissions are set under `all` and for a specific package, the package-specific settings take precedence. The `read` and `write` attributes take one of `user`, `group`, and `world`.
packages:
all:
permissions:
write: group
group: spack
my_app:
permissions:
read: group
group: my_team
