This allows <bsd.lib.mk> to correctly set the RPATH of libraries that
use USE_SHLIBDIR=yes to /lib, so that dependent libraries can be found
from /lib when /usr/lib isn't mounted yet.
This was the intention of the _LIBLDOPTS support in <bsd.lib.mk>.
Fixes problem reported by Dan Carosone with when /sbin/cgdconfig is
dynamically linked against libcrypto.so but not libcrypt.so (it was
relying upon libcrypto.so to pull in libcrypt.so).
337f8776b0