Fixes https://github.com/harfbuzz/harfbuzz/issues/1541

* Add --with-graphite2 to macOS
* Add a dummy ragel script for psvita

Fixes https://github.com/harfbuzz/harfbuzz/issues/1612

MSVC does not set __cplusplus to the latest standard and also it does not like redefining some keywords.

It is not needed anyway

This allows partial-instantiating custom Null object for template Lookup<T>.
Before, this had to be handcoded per instantiation.  Apparently I missed
adding one for AAT::ankr.lookupTable, so it was getting the wrong (generic)
null for Lookup object, which is wrong and unsafe.

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=944346

Isn't absolutely needed.  But helps.

Let's see if I can make a release on Mac...

so they don't use deprecated variable

* add check to FDArray::serialize

* add test files

* fix off by one

Fixes fvar table sanitization where there are no named instance
by allowing zero length ranges starting from Null() address.

Fixes #1607

Add a flag to hb_buffer_t to prevent the insertion of dotted circles on incorrect character sequences. 

Current behavior unchanged if this flag is not set (and it isn't by default).

I stumbled over this when trying to upgrade the version of HarfBuzz used by
LibreOffice to 3.2.1 (see <https://gerrit.libreoffice.org/plugins/gitiles/core/
+/b7ddc514bff9bdf682abae537f990aa01dc2c0fb%5E!/> "Upgrade to latest
HarfBuzz 2.3.1"), where building with MSVC 2017 failed like

> c:\cygwin\home\tdf\lode\jenkins\workspace\gerrit_windows\workdir\unpackedtarball\harfbuzz\src\hb-atomic.hh(272): error C2440: 'reinterpret_cast': cannot convert from 'const int *' to 'std::atomic<int> *'
> c:\cygwin\home\tdf\lode\jenkins\workspace\gerrit_windows\workdir\unpackedtarball\harfbuzz\src\hb-atomic.hh(272): note: Conversion loses qualifiers
> c:\cygwin\home\tdf\lode\jenkins\workspace\gerrit_windows\workdir\unpackedtarball\harfbuzz\src\hb-atomic.hh(272): error C2227: left of '->load' must point to class/struct/union/generic type

(see <https://ci.libreoffice.org/job/gerrit_windows/29916/>).

I added all the necessary "const" to make building of HarfBuzz 2.3.1 with
MSVC 2017 succeed for me.  There may be more missing at least conceptually.

As vscode is going to support it soon

It makes a hb_face_t from IDWriteFontFace, useful when using
DirectWrite facilities for font selection, loading and rendering
but using harfbuzz for shaping.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1596

in case called immediately after init()