allow cfg(bootstrap)

Author: RalfJung

src/tools/miri/Cargo.toml

@@ -78,6 +78,7 @@ native-lib = ["dep:libffi", "dep:libloading", "dep:capstone", "dep:ipc-channel",
 
 [lints.rust.unexpected_cfgs]
 level = "warn"
+check-cfg = ['cfg(bootstrap)']
 
 # Be aware that this file is inside a workspace when used via the
 # submodule in the rustc repo. That means there are many cargo features