daemon: make --inetd and --detach incompatible

Since --inetd makes main return with the result of execute() before
daemonize is gets called, these two options are already incompatible.

Document it, and add an error if attempted.

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-daemon.txt

@@ -78,7 +78,8 @@ OPTIONS
 
 --inetd::
 	Have the server run as an inetd service. Implies --syslog.
-	Incompatible with --port, --listen, --user and --group options.
+	Incompatible with --detach, --port, --listen, --user and --group
+	options.
 
 --listen=<host_or_ipaddr>::
 	Listen on a specific IP address or hostname.  IP addresses can

daemon.c

@@ -23,10 +23,10 @@ static const char daemon_usage[] =
 "           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
 "           [--user-path | --user-path=<path>]\n"
 "           [--interpolated-path=<path>]\n"
-"           [--reuseaddr] [--detach] [--pid-file=<file>]\n"
+"           [--reuseaddr] [--pid-file=<file>]\n"
 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
-"                      [--user=<user> [--group=<group>]]\n"
+"                      [--detach] [--user=<user> [--group=<group>]]\n"
 "           [<directory>...]";
 
 /* List of acceptable pathname prefixes */
@@ -1128,8 +1128,8 @@ int main(int argc, char **argv)
 		/* avoid splitting a message in the middle */
 		setvbuf(stderr, NULL, _IOFBF, 4096);
 
-	if (inetd_mode && (group_name || user_name))
-		die("--user and --group are incompatible with --inetd");
+	if (inetd_mode && (detach || group_name || user_name))
+		die("--detach, --user and --group are incompatible with --inetd");
 
 	if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
 		die("--listen= and --port= are incompatible with --inetd");