HarfBuzz on MacOS

[Pankaj Jangid]

I have following output from pkg-config:

pankaj@Pankajs-MacBook-Pro emacs % pkg-config --libs "harfbuzz >= 1.2.3"
-L/usr/local/Cellar/harfbuzz/2.6.4/lib -lharfbuzz
pankaj@Pankajs-MacBook-Pro emacs % pkg-config --cflags "harfbuzz >= 1.2.3"
-I/usr/local/Cellar/harfbuzz/2.6.4/include/harfbuzz
-I/usr/local/Cellar/glib/2.62.2/include/glib-2.0
-I/usr/local/Cellar/glib/2.62.2/lib/glib-2.0/include
-I/usr/local/opt/gettext/include -I/usr/local/Cellar/pcre/8.43/include
-I/usr/local/Cellar/graphite2/1.3.13/include

But even when I use "./configure --with-harfbuzz", the output of
configure script is

...
Does Emacs use -lgnutls?                                yes
Does Emacs use -lxml2?                                  yes
Does Emacs use -lfreetype?                              no
Does Emacs use HarfBuzz?                                no
...

I have two questions now.

1. Does HarfBuzz make any difference on MacOS?
2. Why HarfBuzz is not selected by the configure script?

I am building on MacOS 10.15.1, Emacs commit is
2e92f176a3ae68ed6fcf9f07c173c61a497f33fd.

Regards,
-- 
Pankaj Jangid