Rust: Workbench reads user "rustc-wrapper" configuration, leading to launch issues

[theCapypara]

At the moment it seems that the cargo process launched through Workbench to build the Rust demos reads the user's ~/.cargo/config file.

If Workbench is running in a Flatpak it still reads this file. This can lead to issues if a rustc-wrapper is defined. In that case Workbench/Cargo will launch that wrapper instead. However since it is trying to launch it in the Flatpak sandbox, this will most likely fail due to missing libraries.

Other configuration values may cause similiar issues. It may just be best to keep this sandboxed and don't read ~/.cargo/config if Workbench is running as a Flatpak.

[sonnyp]

FWIW This is only a problem when built locally.