Add --disable-new-dtags option when setting rpath

Some newer Linux systems enable the "new dtags" linker option by
default. With this option --rpath sets DT_RUNPATH instead of DT_RPATH.
Unfortunately, DT_RUNPATH is not applied transitively when searching
for indirect dependencies, breaking the Lucy test executable. See

    https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/1253638
    https://sourceware.org/bugzilla/show_bug.cgi?id=13945