#5 Improve const correctness

[Markus Elfring]

Would you like to apply the advices from the article
"http://en.wikipedia.org/wiki/Const_correctness" to
your sources?
I suggest to add the key word "const" to the type
specifiers for parameters like the following examples.
-
http://cvs.sourceforge.net/viewcvs.py/cpcd/cpcd/src/cpcd.h?rev=1.3&view=markup
ip, url (function "process_update")
ip, net_name, port_restrict (function "verify_node")
url (function "cache_known_bad")

-
http://cvs.sourceforge.net/viewcvs.py/cpcd/cpcd/src/cpcd_util.h?rev=1.2&view=markup
url (function "clean_url_r")
data (function "verify_url")
file, hostname, portnum (function "ping_cache_.+")
file_loc (functions ".+_pid_file")
skt, the_line (function "write_line_to_socket")