A Path property was used in the old index gnat crate to force the use of the system compiler in crates that depend on native libraries (e.g., eagle_lander). That property no longer exists in the new index syntax.

I am not sure reintroducing it is the best course of action yet (it might depend on the rework of native packages); but I'm making a note here not to forget about this issue. The current situation is that crates that depend on the native compiler will fail if attempted to be build with a non-native one (although all its native dependencies will be installed), but will work normally otherwise.