The `spack.architecture` module contains an `Arch` class that is very similar to `spack.spec.ArchSpec` but points to platform, operating system and target objects rather than "names". There's a TODO in the class since 2016:
abb0f6e27c/lib/spack/spack/architecture.py (L70-L75)
and this PR basically addresses that. Since there are just a few places where the `Arch` class was used, here we query the relevant platform objects where they are needed directly from `spack.platforms`. This permits to clean the code from vestigial logic.
Modifications:
- [x] Remove the `spack.architecture` module and replace its use by `spack.platforms`
- [x] Remove unneeded tests
* Use gnuconfig package for config file replacement for RISC-V.
This extends the changes in #26035 to handle RISC-V. Before this change,
many packages fail to configure on riscv64 due to config.guess being too
old to know about RISC-V. This is seen out of the box when clingo fails
to build from source due to pkgconfig failing to configure, throwing
error: "configure: error: cannot guess build type; you must specify one".
* Add riscv64 architecture
* Update vendored archspec from upstream project.
These archspec updates include changes needed to support riscv64.
* Update archspec's __init__.py to reflect the commit hash of archspec being used.
Cherry-picked from #25564 so this is standalone.
With this PR we can activate an environment in Spack itself, without computing changes to environment variables only necessary for "shell aware" env activation.
1. Activating an environment:
```python
spack.environment.activate(Environment(xyz)) -> None
```
this basically just sets `_active_environment` and modifies some config scopes.
2. Activating an environment **and** getting environment variable modifications for the shell:
```python
spack.environment.shell.activate(Environment(xyz)) -> EnvironmentModifications
```
This should make it easier/faster to do unit tests and scripting with spack, without the cli interface.
