how to modify the `variable` property?

[Werner LEMBERG <wl@xxxxxxx>]

[Fontconfig version 2.14.1]


For technical reasons I want to reject OpenType Variation Fonts
completely.  This means that I also want to reject named instances,
that is, fonts with a face index larger than 0xFFFF (which Fontconfig
tags as non-variable).  I added the following to my
`.config/fontconfig/fonts.conf` file

```
<fontconfig>
  <!-- set 'variable' property to 'true' for named instances -->
  <match target="font">
    <test name="index" compare="more">
      <int>65535</int>
    </test>
    <edit name="variable" mode="assign">
      <bool>true</bool>
    </edit>
  </match>

  <!-- reject variation fonts -->
  <selectfont>
    <rejectfont>
      <pattern>
        <patelt name="variable"><bool>true</bool></patelt>
      </pattern>
    </rejectfont>
  </selectfont>
</fontconfig>
```

but the `<match>` block has no effect.  Please help.


    Werner