[bonzini]

Yeah that's very much a special-purpose tool and cannot be used if for example the build.rs file has different output for Linux/macOS/Windows.

I like the Meson model where the meta-build system is opinionated (not as much as cargo in the case of Meson, but still quite a bit) but, at the same time, it doesn't itself take care of the build. The build is done via build.ninja, static analysis and other tools use compile_commands.json. There is no reason why cargo couldn't work this way and even preserve the same command line interface.