We now allow things like "dlig on" / "dlig=on".

It's defined in hb-private.h already.

Towards accepting CSS font-feature-settings strings.

https://bugzilla.redhat.com/show_bug.cgi?id=1001645

https://bugs.freedesktop.org/show_bug.cgi?id=65544

Using a ragel machine.

Using a ragel machine.

Before, if one called hb_shape() without setting script, language, and
direction on the buffer, hb_shape() was calling
hb_buffer_guess_segment_properties() on the user's behalf to guess
these.

This is very dangerous, since any serious user of HarfBuzz must set
these properly (specially important is direction).  So now, we don't
guess properties by default.  People not setting direction will get
an abort() now.  If the old behavior is desired (fragile, good for
simple testing only), users can call
hb_buffer_guess_segment_properties() on the buffer just before calling
hb_shape().

Ouch

And hb_buffer_content_type_t and enum values.

Should give us some performance boost.

Not optimized yet.  Eats babies.  And no shaper uses the shape_plan.

Add global shape_plan.  Unused so far.

Choose using shaper name "old".

Does not attempt to handle clusters in a Uniscribe- or HarfBuzz-compatible way;
just returns the original string indexes that CT maintains. These may even be
out-of-order in the case of reordrant glyphs.

We're free!  Lazy or immediate...

Also remove shaper_options argument to hb_shape_full().  That was
unused and for "future".  Let it go.

More shaper API coming in preparation for plan/planned API.

To be modified, a lot.

We need this to set data on objects safely without worrying that some
other thread unsets it by setting it at the same time.