Re: make doc error on current master

>> A solution to this particular problem is now easy: Replace
>> `NotoSerifCJK-VF.otf.ttc` with the fully equivalent (but slightly
>> larger) file `NotoSerifCJK-VF.ttf.ttc`, which can be found here:
>> https://github.com/notofonts/noto-cjk/blob/main/Serif/Variable/OTC/NotoSerifCJK-VF.ttf.ttc
> 
> I don't want to touch a file provided by a distro package.

OK.  Then I suggest to manually filter out this font in a local
FontConfig configuration file.  For example, append the following to
file `~/.fonts.conf` (or `~/.config/fontconfig/fonts.conf`) right
before the closing `</fontconfig>` tag:

```xml
  <selectfont>
     <rejectfont>
        <glob>/usr/share/fonts/google-noto-serif-cjk-vf-fonts/NotoSerifCJK-VF.ttc</glob>
    </rejectfont>
  </selectfont>
```

If the file doesn't exist, create it with the following contents
instead:

```xml
<?xml version="1.0"?><!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <selectfont>
     <rejectfont>
        <glob>/usr/share/fonts/google-noto-serif-cjk-vf-fonts/NotoSerifCJK-VF.ttc</glob>
    </rejectfont>
  </selectfont>
</fontconfig>
```


    Werner