Building DHCP 4.4.1 using libbind from BIND 9.14.x

I'm trying to build DHCP 4.4.1. There are many build errors because of missing definitions, e.g.:

../includes/tree.h:307:30: error: unknown type name 'isc_boolean_t'; did you mean 'isc_token_t'?

When building against BIND 9.12.4, I'm able to work around these by adding #include <isc/boolean.h> and similarly for int.h to dhcpd.h and omapip.h. However, that is no longer a viable fix when building against BIND 9.14.x, because those header files are no longer part of BIND in that release.

Is there a recommended approach for building DHCP 4.4.1?