wrap: Ignore Homebrew paths
The installation guide for Homebrew encourages users to prepend Homebrew directory in the environment variable PATH.
However, with Homebrew, users might install a newer glibc, or other risky packages. And that could interfere with the container runtime setup and potentially causing games to fail, as reported in https://github.com/ValveSoftware/steam-runtime/issues/569.
Given that Homebrew files should only be used by the packages installed within Homebrew itself, it is safe for us to completely skip over its directories when setting up a container.
Fixes: steamrt/tasks#247
Edited by Ludovico de Nittis