cross-system-type
cross-system-library-subpath
Adjust installation tools to support cross-installation (i.e., installation for a platform other than the current one) as triggered by "system.rktd" in "lib" having different information than the running Racket executable.
vector-set-performance-stats!
The layer is now redundant, since everything left in "pkgs" is in the "racket-pkgs" category.