Function sysroot_file_name 

pub(crate) fn sysroot_file_name(
    artifact: &Artifact,
    filename: &Utf8Path,
) -> Result<String>

Name an artifact gets inside the sysroot.

Cargo reports an uplifted, hash-free .rlib for these crates but a hashed .rmeta, and rustc pairs the two by the infix between lib<crate> and the extension, so we cannot reuse cargo’s names. Naming by crate keeps the pairing intact.