Consider removing the default test_description.json or add ability to disable musl builds

[mtjhrc]

In the rust-vmm/vhost-device repository: I'm trying to move the vhost-user-gpu from the staging directory into the "main" directory:
rust-vmm/vhost-device#801

The problem is that staging uses a custom test configuration, where I have disabled building the gpu device with musl.
This device links a lot of native dependencies and I would like to build it only with the gnu libc. As far as I can tell this is currently not achievable. (or is it somehow?)

I also saw there is vhost-device-sound which seems to have the same problem with linking to native libraries, the solution there disables all of the backends on musl build except the "null" backend. (So I think the device is not really usable, only the unit tests run).
For the gpu device, I'd rather not build it with musl at all, otherwise all of the functionality has to be conditionally compiled with #[cfg(target_env = "gnu")] attributes. (this was discussed here: rust-vmm/vhost-device#797 (comment) )

So my proposal would be to just remove the default test_description.json and have a version of that for each repository (where it can be better configured). The other option could be some mechanism to disable musl builds for specific crates in the workspace - this seems more complicated though.

[stefano-garzarella]

So my proposal would be to just remove the default test_description.json and have a version of that for each repository (where it can be better configured).

This is already possible, indeed in https://github.com/rust-vmm/vhost we don't use the default, but we use a custom one (https://github.com/rust-vmm/vhost/blob/main/.buildkite/rust-vmm-ci-tests.json), so in vhost-device we can do the same, where we already have a custom one for staging, we can add another one for the main branch. We just need to change the configuration in buildkite.

[mtjhrc]

Oh, so it is already possible - no need to change anything then.