1.9.0 dnsmasq cannot start when use-dnsmasq on dhcp with CIDR not in 8,16,24

I try to let dnsmasq take over all dhcp requests, but if I set domain-name in dhcp subnet, dnsmasq says syntax error.

Tried on both erl and erx, 1.9.0.

Here is my dhcp config:

show service dhcp-server shared-network-name dhcp-lan 
 authoritative disable
 subnet 192.168.32.0/20 {
     default-router 192.168.32.1
     dns-server 192.168.32.1
     domain-name int.xxxx.com
     lease 86400
     start 192.168.40.0 {
         stop 192.168.46.255
     }
     static-mapping dev {
         ip-address xxxxxx
         mac-address 1xxxxxx
     }
     static-mapping sskaje {
         ip-address xxxxxx
         mac-address xxxxxx
     }
 }

generated dnsmasq-dhcp-config.conf

###shared-network dhcp-lan

        #subnet 192.168.32.0/20
                dhcp-range=set:dhcplan,192.168.40.0,192.168.46.255,255.255.240.0,86400
                domain=int.xxxxxx.com,192.168.32.0/20,local
                dhcp-option=tag:dhcplan,option:domain-name,int.xxxxxx.com
                dhcp-option=tag:dhcplan,option:router,192.168.32.1
                dhcp-option=tag:dhcplan,option:dns-server,192.168.32.1

                #static reservations for subnet 192.168.32.0/20
                dhcp-host=xxxxxx   #dev
                host-record=dev.int.xx.com,192.168.36.20,86400        #dev.int.youbaowuxian.com
                dhcp-host=xxxxxx   #sskaje
                host-record=sskaje.int.xxxx.com,192.168.36.50,86400     #sskaje.int.youbaowuxian.com
        #end of subnet 192.168.32.0/20

###end of shared-network dhcp-lan

The error line is 

                domain=int.xxxxxx.com,192.168.32.0/20,local

If I remove the ',local', and restart dnsmasq, it worked.

According to dnsmasq man page, 

If the address range is given as ip-address/network-size, then a additional flag 
"local" may be supplied which has the effect of adding --local declarations for 
forward and reverse DNS queries. Eg. --domain=thekelleys.org.uk,192.168.0.0/24,
local is identical to --domain=thekelleys.org.uk,192.168.0.0/24 
--local=/thekelleys.org.uk/ --local=/0.168.192.in-addr.arpa/ The network size 
must be 8, 16 or 24 for this to be legal.

The CIDR I'm using is /20, not accepted by dnsmasq.

Can you add some extra 'if' before adding that ',local' ?