Comment on macOS usage in README.rst

[cmconnelly]

The README file says

Your Emacs must be built with Harfbuzz enabled -- this is the default as of Emacs 27.1, but obscure platforms may not support it; You can check by typing C-h v system-configuration-features. Search for the word HARFBUZZ.

but that doesn't seem to apply on the Mac, where Emacs's configure script happily refuses to use HarfBuzz, libotf or libxft, and ignores the use of –with-harfbuzz and –with-cairo, but ligatures seem to work fine (built from master; currently released Emacs locks up with a screaming fit). Presumably Emacs is just using macOS's native font library.

(It might be possible to make Emacs build as an X application rather than using the macOS window manager, and in that case you might be able to use Cairo, HarfBuzz, and friends, but I'm happy with the Mac version on my Mac.)

[mickeynp]

Hm. I'm not a Mac person, so I can't explain why it works. Can you create a PR that amends the README to include the part about Macs?

As for the hanging: that is unfortunately an issue with Emacs 27.1 and the upcoming 27.2 that is only resolved in master.