2d0cb31d30
This fixes the case where we try to re-build & re-install rust to the same prefix (without uninstalling) while using an llvm-root that is the same as the prefix. Without this, builds like that fail with: 'error: multiple dylib candidates for `std` found' See https://github.com/jmesmon/meta-rust/issues/6 for some details. May also be related to #20342.