Get rid of the ugly CMD_CHFLAG macro and use a const string (eg "dDU") in the

command entry structs and a couple of functions to check/set the flags.

cmd-select-prompt.c

@@ -33,7 +33,7 @@ int	cmd_select_prompt_callback(void *, const char *);
 const struct cmd_entry cmd_select_prompt_entry = {
 	"select-prompt", NULL,
 	CMD_TARGET_CLIENT_USAGE,
-	0, 0,
+	0, "",
 	cmd_target_init,
 	cmd_target_parse,
 	cmd_select_prompt_exec,