libink: a message bus is not a peer

libink was written against the only bus it had, its own, where the
peer on the other end is the client.  A broker is not: it routes for
senders it names itself, expects a DESTINATION on anything addressed
through it, and answers on its own schedule rather than next.

Runlevels go on the wire as S and N rather than the digits Finit
keeps internally, since that is what a caller outside Finit means by
one.

The library stays a convenience library, linked into finit and
initctl and installed nowhere: the ABI promise waits until libink is
its own project.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/lib/setup.sh

@@ -330,7 +330,6 @@ export SYSROOT
 top_builddir="${top_builddir:-$TEST_DIR/..}"
 sysroot_finit="$SYSROOT/sbin/finit"
 built_finit="$top_builddir/src/finit"
-[ -x "$top_builddir/src/.libs/finit" ] && built_finit="$top_builddir/src/.libs/finit"
 
 if [ -x "$built_finit" ] && [ -e "$sysroot_finit" ] && ! cmp -s "$built_finit" "$sysroot_finit"; then
 	fail "Stale $sysroot_finit, run 'make -C test setup-chroot' or use 'make check'"