Implement Custom Font Collections on pre-Windows 10 systems

Commit 68818db0ec0e9c308c8a0772d46af551f439b32c (build a
IDWriteFontCollection1 of our FR_PRIVATE fonts, 2022-01-11) used
dwrite_3.h, which has API available only starting from Windows 10.
For pre-Windows 10 versions, there is a different way to implement
this, as explained at

https://learn.microsoft.com/en-us/windows/win32/directwrite/custom-font-collections

This change implements that more complex way as a fallback, until
we bump the baseline. Allows to not fall back to gdi in Skia, like
with the original commit, just on older Windows versions.

Change-Id: Ieca13e4a04bc72ce877ab9b512c7821d5466cb70
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/172090
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

0 files changed, 0 insertions, 0 deletions