Tag the libraries with check_ to prevent them being installed
by "make install". Additionally make check requires .so to be
create which requires .lai files to be constructed which, in
turn, requires -rpath <dir> as part of "linking" the .la file.
the test-async plugin uses ns_query_hookasync() at the
NS_QUERY_DONE_SEND hook point to call an asynchronous function.
the only effect is to change the query response code to "NOTIMP",
so we can confirm that the hook ran and resumed correctly.