Nice work on the installation script! It's good to see that it works for both rpm and deb based distributions.
When I wrote the original version of this, I tried to lock down specific commits in the git clones, as the underlying branches were changing (and breaking!) all the time. This was only partially successful, as some of the commands pull more from git (ghcjs-boot if I remember correctly) .
Do you think that the underlying tooling has stabilised enough that this is no longer a likely problem?