fonts/harfbuzz on netbsd-7 amd64

[John Klos <john%zia.io@localhost>]

...
  CXX      libharfbuzz_la-hb-glib.lo
  CXX      libharfbuzz_la-hb-ft.lo
In file included from hb-ft.cc:32:0:
hb-ft.h:34:22: fatal error: ft2build.h: No such file or directory
 #include <ft2build.h>
                      ^
compilation terminated.
Makefile:2090: recipe for target 'libharfbuzz_la-hb-ft.lo' failed
gmake[4]: *** [libharfbuzz_la-hb-ft.lo] Error 1
gmake[4]: *** Waiting for unfinished jobs....