NixOS/nixpkgs — pull request #513 by offlinehacker (2013-05-10 00:54:54+00:00)
Title: firefoxWrapper: Add libcanberra gtk module to firefox

Libcanberra is a simple abstract interface for playing event sounds.

I don't know if this implementation is correct, but i got warnings while starting firefox(on debian running nix), so including libcamberra as gtk module fixes them.