New comment by Hnaguski on void-packages repository

https://github.com/void-linux/void-packages/pull/32238#issuecomment-890523554

Comment:
Well it seems like this build is failing because dolphin now requires mGBA when building. The [dolphin wiki says](https://github.com/dolphin-emu/dolphin/wiki/Building-for-Linux#checkout-dolphin) to run `git submodule update --init Externals/mGBA` after cloning the git repository. Could someone point me in the right direction as to how to implement this in the package?