fallout-ce: Fix broken game load/save due to case sensitive filesystem

[avnik]

Description of changes

Fix fallout-ce/fallout2-ce issue with save/load games if game data copied with wrong case of filenames.
(Include fix from alexbatalov/fallout1-ce#119 PR, as well as my own port of this fix for fallout2-ce)

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.05 Release Notes (or backporting 23.05 and 23.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[hughobrien]

I have an outstanding PR also on that repo.

alexbatalov/fallout1-ce#128

My preference is to get the upstream change merged rather than have our own quasi-fork, but it's certainly a slow process.

Let's ask for those changes to be merged and if we don't make progress we can use these patches.

[avnik]

@hughobrien 3 month, no reactions from upstream