[Fontconfig] How to ignore OpenType Collection fonts

[Masamichi Hosoda]

Hello,

I'd like to ignore OpenType Collection (OTC) fonts
(NotoSansCJK.ttc and SourceHanSans.ttc etc.).
Those file name extension is `*.ttc'.
Those fontformat is `CFF'.

On the other hand, I'd like to not ignore TrueType Collection (TTC) fonts
(msmincho.ttc and msgothic.ttc etc.).
Those file name extension is `*.ttc'. It's same as OTC fonts.
Those fontformat is `TrueType'.

So I've tried the following settings.

```
<selectfont>
  <rejectfont>
    <glob>*.ttc</glob>
  </rejectfont>
  <acceptfont>
    <pattern>
      <patelt name="fontformat">
	<string>TrueType</string>
      </patelt>
    </pattern>
  </acceptfont>
</selectfont>
```

It ignores OTC fonts.
However it ignores TTC fonts, not only OTC fonts.

Is there a way to ignore the only OTC fonts?

Thanks