initialize phantom points from metrics from htmx/vmtx & glyf bbox before execution
added source file hb-ot-hmtx-table.cc to call glyf from hmtx/vmtx indirectly & temporarily, workaround a cyclic reference between the two
Re-implemented & repurposed CFF:remap_t as hb_map2_t (moved to hb-ot-layout-common.hh) for two-way mapping for use by index map subsetting.
Hooked up HVAR subsetter through _subset2.
Some renaming in CFF code.
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.
It makes a hb_face_t from IDWriteFontFace, useful when using
DirectWrite facilities for font selection, loading and rendering
but using harfbuzz for shaping.
For some reasons djgpp doesn't understand "unsigned int" can be same
with one of uint*_t anyway so lets do that for it explicitly.
Just to note, our CI's djgpp is based GCC 7.2.0 and isn't old.