New comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/23530#issuecomment-657238420

Comment:
Having tried this on my system, I got:

- `pavucontrol`, without `adwaita`, doesn't have icons
- `pavucontrol`, with `adwaita` but without `librsvg`, shows the proper icons, but prints a warning about being unable to load a pixbuf from an SVG file
- `nwgbar` (from `nwg-launchers`, not yet packaged), without adwaita, doesn't have icons
- `nwgbar`, with `adwaita` but without `librsvg`, crashses with `SIGABRT` due to being unable to load pixbufs from SVG. This is likely caused by not having a fallback

Therefore, I think what we need to do depends on the themes we currently ship. Are there themes that only ship PNGs? If not, we could make `gtk+3` depend on `librsvg`, because:

```
most gtk applications need adwaita theme to work properly -> some applications crash when SVG icons exist but they can't load them -> gtk should depend on a library to load svg icons OR those applications should depend on librsvg
```

I'm in favor of solving it for `gtk+3`, because otherwise all applications will still print warnings when using PNG icons, and tracking down applications that misbehave is time consuming and error prone. Furthermore, `librsvg` is a small package compared to `gtk+3`.