Motivation for this change

I am writing some nix expressions to patch some Nintendo GameCube images.
Wiimm's ISO Tools are helpful for this, and what I normally use.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

I tried a few new things with this package that I wasn't confident around:

• Setting sourceRoot
  Everything that needs to be built is under project/. I saw that some other packages set sourceRoot.
  Am I doing this correctly?

• Disabling Hardening
  This package doesn't build unless we disable some hardening around format strings.

• No Tags
  The GitHub repository does not have tags, so I added the rev directly. The version is from this commit:

$ git show --no-patch
commit 7f41a7f1edf2bd1698482cafe1b10f6b87b73da7 (HEAD -> master, origin/master, origin/HEAD)
Author: Wiimm <none>
Date:   Sat Aug 22 10:37:50 2020 +0200

    WIT v3.03b: Intermediate version (no release)

• Broken /usr/bin/env ... Scripts
  I'm fixing this with sed, using an approach I saw in pkgs/shells/xonsh/default.nix.