Another information:

I have other programs on my foreign system (installed via guix) that produce sound well, without any issues. They include:

espeak and kdenlive.

Also, I did try making the union-build use copies instead of symlinks using

(union-build ... #:symlink copy-recursively) but that didn't work out either.

Now, I'm going to take a look at fixing the pkg-config rules, and will be updating this thread should that resolve this issue.

On Sat, Sep 26, 2020 at 12:21 PM Prafulla Giri <pratheblackdiamond@gmail.com> wrote:

I forgot to mention, but the union-build works. If one `guix build`s the union package, and cd into the /gnu/store/...-union-build, one will see that things are there as it should be (lib/normal-alsa-*.so and lib/alsa-lib/*pulse*.so).

It's just that aegisub seems to be looking from the /gnu/store/normal-alsa-lib-dir instead of /gnu/store/union-alsa-package.