They were previously being defined by cddl/lib/Makefile.inc, and as of
commit 4ae6991228 were being overridden by defaults in bsd.own.mk,
which changed SHLIBDIR to /usr/lib.
Reported by: Domagoj Stolfa <ds815@cam.ac.uk>
Fixes: 4ae6991228 ("dtrace: Add WITH_DTRACE_ASAN")