What were you thinking? ;)

Needed to make ubsan work.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1174

See also https://github.com/harfbuzz/harfbuzz/pull/1169

See also https://github.com/harfbuzz/harfbuzz/pull/1169

See also https://github.com/harfbuzz/harfbuzz/pull/1169

See also https://github.com/harfbuzz/harfbuzz/pull/1169

We might reintroduce it later, but for now remove, as it was unused.
Some things that should have been in this object (drop_hints, etc)
are already in hb_subset_input_t.  So, for now, keep everything there.

New API:
+hb_face_collect_unicodes
+hb_face_collect_variation_selectors
+hb_face_collect_variation_unicodes

Sorry for the noise, downstream custom builders.  Please adjust.

When collecting all codepoints in the cmap avoid using large amount of memory for fonts that declare coverage over all 32 bit integers.

Add the fuzzer test case for feature collection timeout.

New API:
+hb_set_is_subset()

Right now only Old Italic is marked as such.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1000

[subset] sketch out support for a call that lists all codepoints present in a font. Implement support for it in format 4 cmap sub table.

* [subset] sanitize individual DeviceRecord's as part of hdmx sanitization.

* [subset] Fix out of bounds read with non-two byte align glyphs.

* [subset] Just use size_device_record >= DeviceRecord::min_size.

* [subset] Add TODO.

* [subset] Re-order checks in hdmx sanitize.

Before 1.7.5, we were setting -fno-exceptions etc on CXXFLAGS. In 1.7.6
we set it as CPPFLAGS. Try fixing. Also, I'm fairly sure it's safe to
set these unconditionally.

Fixes https://github.com/harfbuzz/harfbuzz/issues/880 (or so I hope)