Cleaned up git-daemon virtual hosting support.

Cleaned up git-daemon virtual hosting support.

Standardized on lowercase hostnames from client.

Added interpolation values for the IP address, port and
canonical hostname of the server as it is contacted and
named by the client and passed in via the extended args.

Added --listen=host_or_ipaddr option suport.  Renamed port
variable as "listen_port" correspondingly as well.

Documented mutual exclusivity of --inetd option with
    --user, --group, --listen and --port options.

Added compat/inet_pton.c from Paul Vixie as needed.

Small memory leaks need to be cleaned up still.

Signed-off-by: Jon Loeliger <jdl@jdl.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>