.env(bootstrap::util::dylib_path_var(),
env::join_paths(&dylib_path).unwrap());
- // Pass the `rustbuild` feature flag to crates which rustbuild is
- // building. See the comment in bootstrap/lib.rs where this env var is
- // set for more details.
- if env::var_os("RUSTBUILD_UNSTABLE").is_some() {
- cmd.arg("--cfg").arg("rustbuild");
+ // Force all crates compiled by this compiler to (a) be unstable and (b)
+ // allow the `rustc_private` feature to link to other unstable crates
+ // also in the sysroot.
+ if env::var_os("RUSTC_FORCE_UNSTABLE").is_some() {
+ cmd.arg("-Z").arg("force-unstable-if-unmarked");
}
std::process::exit(match cmd.status() {