add --tftp-no-fail to ignore missing tftp root

src/dnsmasq.h

@@ -240,7 +240,8 @@ struct event_desc {
 #define OPT_LOCAL_SERVICE  49
 #define OPT_LOOP_DETECT    50
 #define OPT_EXTRALOG       51
-#define OPT_LAST           52
+#define OPT_TFTP_NO_FAIL   52
+#define OPT_LAST           53
 
 /* extra flags for my_syslog, we use a couple of facilities since they are known 
    not to occupy the same bits as priorities, no matter how syslog.h is set up. */
@@ -901,6 +902,7 @@ struct addr_list {
 struct tftp_prefix {
   char *interface;
   char *prefix;
+  int missing;
   struct tftp_prefix *next;
 };