glibc tends to return PTR entries when AI_CANONNAME flag is set; now using
BIND internal calls such as res_search to explicitly ask for CNAMErecords; and
manually parsing the DNS response to circumvent varying AI_CANONNAME behavior
across platforms
updated DNS test to echo the entire CNAME chain
freeing up space allocating by calloc(...); few more memory leaks to fix ...
freeing blocks allocated for CNAME chains; no memory leaks