Add --script-on-renewal option.

man/dnsmasq.8

@@ -1554,7 +1554,8 @@ address of the host (or DUID for IPv6) , the IP address, and the hostname,
 if known. "add" means a lease has been created, "del" means it has
 been destroyed, "old" is a notification of an existing lease when
 dnsmasq starts or a change to MAC address or hostname of an existing
-lease (also, lease length or expiry and client-id, if \fB--leasefile-ro\fP is set).
+lease (also, lease length or expiry and client-id, if \fB--leasefile-ro\fP is set
+and lease expiry if \fB--script-on-renewal\fP is set).
 If the MAC address is from a network type other than ethernet,
 it will have the network type prepended, eg "06-01:23:45:67:89:ab" for
 token ring. The process is run as root (assuming that dnsmasq was originally run as
@@ -1744,6 +1745,10 @@ stdout and exit with zero exit code. Setting this
 option also forces the leasechange script to be called on changes
 to the client-id and lease length and expiry time.
 .TP
+.B --script-on-renewal
+Call the dhcp script when the lease expiry time changes, for instance when the
+lease is renewed.
+.TP
 .B --bridge-interface=<interface>,<alias>[,<alias>]
 Treat DHCP (v4 and v6) requests and IPv6 Router Solicit packets
 arriving at any of the <alias> interfaces as if they had arrived at