res_search() detection: always look for res_search to include -lresolv

res_search() detection: always look for res_search to include -lresolv
	for inet_aton().  May be linked in when not absolutely necessary...
	but no big deal, we'll likely start using res_search over sychronous
	get{host,peer}byname calls anyways.
inet_aton() detection: use link instead of compile