Coverted LDAP_LOG macro to use subsystem ID int values instead of string values

Replace old Id as needed (back-tcl).
Leave updating of contribWare to contributors (for now).

s/exit(0)/exit(EXIT_SUCCESS)/
add <ac/stdlib.h> where needed and other minor header adjustments

Also free <user> in !HAVE_GETPWUID case.

verify uid/gid are positive, not non-negative.

Moved -u (udp) to -c (connectionless).  Connectionless is depreciated
and undocumented.
Added tests for set{,e}{u,g}id to configure.  Use existance of
setuid/setgid to enable feature.  Use seteuid/setegid only if
they exist.
Fixed minor minor leak of username/groupname if specificied
more than once.  (This should actually be an error)

Move socket setup to set_socket(), called before the uid/gid change.