I had no luck setting that `FT2_SUBPIXEL_HINTING` environment variable :scream: but this worked:
```sh
export FREETYPE_PROPERTIES="truetype:interpreter-version=35"
```
The only remaining issue is that Chromium [ignores the override](https://bugs.chromium.org/p/chromium/issues/detail?id=649362), so I had to downgrade freetype:
```sh
sudo xdowngrade /var/cache/xbps/freetype-{,devel-}2.6.5_1.x86_64.xbps
sudo xbps-pkgdb -m hold freetype freetype-devel
```