https://bugzilla.redhat.com/show_bug.cgi?id=2124697
--- Comment #68 from Fabio Valentini decathorpe@gmail.com --- The problem is that RUSTFLAGS are not set automatically, and are not exposed directly, but passed as environment variables to the cargo command in the %cargo_build macro. So there's currently no way to "just set RUSTFLAGS", as that's not really a supported use case right now. So even if your meson setup doesn't override the flags, there's nothing to inherit from the environment - because they are not *set* in the environment.