Closed issue by Veyrdite on void-packages repository

https://github.com/void-linux/void-packages/issues/25584

Description:
### Problem

Printing from Firefox (to a real printer or to a PDF) any page with a font-family of  'Helvetica' leads to this:

![with_adobehelvetica](https://user-images.githubusercontent.com/6168874/95931776-c78de780-0e15-11eb-944f-c29ec91780e3.png)

It should instead look like this:

![without_adobehelvetica](https://user-images.githubusercontent.com/6168874/95931796-d4124000-0e15-11eb-8d64-d0f4c4bcceed.png)

A lot of older-style websites (including a lot of invoices) use Helvetica.  Absolutely everything ends up garbled like this; most often making it completely unreadable.

Chromium is not affected by this issue, only Firefox.

This problem has been around for a really long time (a decade?  I had the same problem in Arch Linux many years back) but I have only recently discovered the cause. 

### Cause & workaround

Firefox cannot handle the Helvetica fonts included in packages font-adobe-100dpi and font-adobe-75dpi.  

Elsewhere (where? link!)  I've read advice that you should not be installing these packages, however on Void they are dependencies of Xorg so that is not an option:

```
$ sudo xbps-remove font-adobe-100dpi font-adobe-75dpi
font-adobe-100dpi-1.0.3_6 in transaction breaks installed pkg `xorg-fonts-7.6_5'
font-adobe-75dpi-1.0.3_6 in transaction breaks installed pkg `xorg-fonts-7.6_5'
Transaction aborted due to unresolved dependencies.

$ sudo xbps-remove font-adobe-100dpi font-adobe-75dpi xorg-fonts
xorg-fonts-7.6_5 in transaction breaks installed pkg `xorg-7.6_5'
Transaction aborted due to unresolved dependencies.
```

As a workaround you can manually remove the offending fonts:

`$ sudo rm /usr/share/fonts/X11/*/helv*`

Firefox will then print perfectly.

### Solutions

I can think of several approaches, but I don't know what would be best.

1. Split xorg-fonts into xorg-fonts-minimal and xorg-fonts-all, so these adobe fonts are not installed by default.  (I _think_ this is how other distros handle this?)
2. Fontconfig magic?
3. Complain upstream to Firefox
4. Patch firefox