Rename ADDLOBJ to ADDLOBJS, along the lines of LIBOBJS, etc..

Rename ADDLOBJ to ADDLOBJS, along the lines of LIBOBJS, etc..

Add ADDLARCHIVEOBJS, so that we can put some stuff from -ldag into the
archive library (so it's self-contained, and the configuration processes
for programs not configured with pcap-config don't have to know about
the DAG library) but not into the shared library (as we can link libpcap
with the DAG shared library, so linking with -lpcap will cause -ldag to
be linked in at run time if necessary).