Currently, module configurations are inconsistent because modulefiles are generated with the configs for the active environment, but are shared among all environments (and spack outside any environment).
This PR fixes that by allowing Spack environments (or other spack config scopes) to define additional sets of modules to generate. Each set of modules can enable either lmod or tcl modules, and contains all of the previously available module configuration. The user defines the name of each module set -- the set configured in Spack by default is named "default", and is the one returned by module manipulation commands in the absence of user intervention.
As part of this change, the module roots configuration moved from the `config` section to inside each module configuration.
Additionally, it adds a feature that the modulefiles for an environment can be configured to be relative to an environment view rather than the underlying prefix. This will not be enabled by default, as it should only be enabled within an environment and for non-default views constructed with separate projections per-spec.
TODO:
- [x] code changes to support multiple module sets
- [x] code changes to support modules relative to a view
- [x] Tests for multiple module configurations
- [x] Tests for modules relative to a view
- [x] Backwards compatibility for module roots from config section
- [x] Backwards compatibility for default module set without the name specified
- [x] Tests for backwards compatibility
This commit removes the DYLD_LIBRARY_PATH variable from the default
modules.yaml for darwin. The rationale behind deleting this
environment variable is that paths in this environment variable take
precedence over the default locations of libraries (usually the
install path of the library), which can lead to linking errors in some
circumstances. For example, executables intended to link with Apple's
system BLAS and LAPACK will instead link to a spack-installed
implementation (e.g., OpenBLAS), causing runtime errors.
These errors are resolved by instead relying on paths set in
DYLD_FALLBACK_LIBRARY_PATH, which is lower in precedence than default
locations of libraries.
