ISC DHCP master builds fail against BIND9.9.11.4-P1

ROBIE is building ISC DHCP master branch against BIND9.9.11.4-P1. These builds are failing due to apparent type changes in BIND9 includes:

Making all in ./bind
/usr/home/tbox/cvs/robie/builds/DHCP.HEAD.disable-dhcpv6/DHCP/bind/bind-9.11.4-P1
already unpacked...
Configuring BIND libraries for DHCP.
Building BIND libraries - this takes some time.

Making all in .
cc -DHAVE_CONFIG_H -I. -I../includes  -I.. -DLOCALSTATEDIR='"/var"'
-g -O2  -Wall -Werror -fno-strict-aliasing -I../includes
-I/usr/home/tbox/cvs/robie/builds/DHCP.HEAD.disable-dhcpv6/DHCP/bind/include
-MT alloc.o -MD -MP -MF .deps/alloc.Tpo -c -o alloc.o alloc.c
In file included from alloc.c:29:
In file included from ../includes/dhcpd.h:97:
../includes/tree.h:307:30: error: type specifier missing, defaults to
'int' [-Werror,-Wimplicit-int]
                           struct option_cache *, isc_boolean_t);
                                                  ^~~~~~~~~~~~~
:

Our most recent release of ISC DHCP, 4.4.1, shipped with 9.11.2-P1.