commit d936ad4582a0017cf88406372d7c08b9896beed6
author Stephan Bergmann <sbergman@redhat.com> Tue Mar 05 17:18:57 2019 +0100
committer Behdad Esfahbod <behdad@behdad.org> Tue Mar 05 12:11:32 2019 -0800
tree 2bc8677c4116d02d417af4e3dfdde3471b400e1d
parent 731b13e4e9190a45e51f855f19e88869a7718d43

Fix hb_atomic_* variants based on C++11 atomics

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.