[PATCH] dwrite: Silence warning for name entries with platform 1/encoding 20.

[Nikolay Sivov]

Hi, Aurélien.

Thanks for the patch. I'm confused as to why with current code 1/20
entries are actually appear to work correctly, even though we treat them
as WCHAR strings in decode_opentype_name(). It's worth exploring how
that happens.

Regarding patch itself, we probably should follow map here [1], to
convert only a subset, and keep the rest, including Khmer (20) entries,
as 7-bit ascii. At least that's what fonttools seems to be doing.

P.S. patch subject should say gdi32, not dwrite.

[1]
https://github.com/fonttools/fonttools/blob/main/Lib/fontTools/misc/encodingTools.py