Part of https://github.com/harfbuzz/harfbuzz/issues/923

Fixes https://github.com/harfbuzz/harfbuzz/issues/935

Fixes https://github.com/harfbuzz/harfbuzz/issues/934

Program: Z:\Users\ebrahim\Desktop\harfbuzz\winbuild\util\.libs\hb-shape.exe
File: ../../src/hb-open-type-private.hh, Line 769

Expression: 0 == (Length & 3)

abnormal program termination

Later to be expanded to a more general tool but for now it only supports CBDT, SVG and CBDT.

* [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.

Automake has this stupid behavior where if your Makefile.am has
syntactic error, it can get to a state that make succeeds but just
ignores broken Makefile.am.  Ouch.

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)

Fixes https://github.com/harfbuzz/harfbuzz/issues/865

Fixes https://github.com/harfbuzz/harfbuzz/issues/901

Fixes https://github.com/harfbuzz/harfbuzz/issues/901

For pre-C99 compilers that do not support round(), we need to have a
simplistic implementation for it, when it is not detected during build
configuration, either via CMake or autotools, by using floor() and
ceil(), which are provided in the pre-C99 compilers.

Please see discussion at commit 86a0ac28 for more details for re-adding
this patch.

[subset] Check for the Null table and not nullptr to detect failure to find a table in glyf accelerator.