Fixes https://github.com/harfbuzz/harfbuzz/issues/537

Fixes https://github.com/harfbuzz/harfbuzz/issues/960

dump-emoji still segfaults.  Needs debugging.

Fixes https://github.com/harfbuzz/harfbuzz/issues/960

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10955

Part of https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10955

Fixes https://github.com/harfbuzz/harfbuzz/issues/1247

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10948

Need to map enum values to numerics since we don't have CoreText headers.

A "&" was missing.  Go back to using pointers that are less error-prone.

out_info might have moved since we copied it's position into local
info var.

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=894937

New API:
+hb_ot_layout_feature_get_name_ids()
+hb_ot_layout_feature_get_characters()

Actual name-fetching API to come later.

New API:
hb_name_id_t
HB_NAME_ID_INVALID

* hb_ot_layout_feature_get_characters
* hb_ot_layout_feature_get_name_ids

However HarfBuzz currently doesn't expose an API for retrieving the actual
information associated with NameId from the `name` table and that should be
done separately.

Was givin a dozen of:

../../src/hb-machinery.hh: In member function ‘bool AAT::ankr::sanitize(hb_sanitize_context_t*) const’:
../../src/hb-machinery.hh:307:23: warning: missed loop optimization, the loop counter may overflow [-Wunsafe-loop-optimizations]
     bool ok = --this->max_ops > 0 &&
               ~~~~~~~~~~~~~~~~~~~~~~
        this->start <= p &&
        ~~~~~~~~~~~~~~~~~~~
        p <= this->end &&
        ~~~~~~~~~~~~~~~^~
        (unsigned int) (this->end - p) >= len;
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I believe those are bogus, but this silences them and does not introduce
logic issues I believe.

We haven't been keeping this updated.  So, while we don't expose the
symbols in the headers if HB_DISABLE_DEPRECATED is defined, we still
always build them.

This is how Uniscribe does it.  So, adjust.  This is only relevant
to fonts that apply cursive positioning from a contextual lookup.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1181

Enabled if script tag 'Qaag' is passed to HarfBuzz.  Disables mark
advance-zeroing and fallback mark-positioning.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1162