EOP: Rust Upgrade for RTS

[luc-blaeser]

Upgrading integrated EOP (#4488) to recent Rust and LLVM dependencies:

• LLVM 18.1.8
• Rust 1.82.0

Special aspects:

• Support for both wasm32 and wasm64.
• Support new dylink.0 instead of dylink.
• Support GOT.mem for RTS in the Motoko linker.
• LLVM LLD (used for wasm-ld) needs a bug fix: [lld][WebAssembly] Fix relocation of Wasm table index with GOT access llvm/llvm-project#104043. Therefore, patching wasm-ld.
• Float formatting is now based on Rust and no longer on musl. There are format changes to output of NaN and infinity. Moreover, one particular output format (hexadecimal float) is no longer supported. Updating the documentation and base library is needed.
• musl is still used in 32-bit but not in 64-bit. In the future, we should get rid of musl entirely. The musl import is rather old, upgrading is complicated as it involves a lot of unwanted dependencies.
• No longer using emscripten for 64-bit Wasm compilation (as there is a nix build issue with latest emscripten). Instead, the clang compiler is directly invoked.
• Adjusting the RTS code in line with the latest Rust features/rules.

Note:

• If your nix-shell crashes with a segmentation fault with this PR, you need to upgrade nix. For this, you need to manually uninstall and re-install nix.

[github-actions]

Comparing from 4657543 to 9f03c0e:
In terms of gas, 5 tests improved and the mean change is -0.0%.
In terms of size, 5 tests regressed and the mean change is +65.9%.

[luc-blaeser]

Closing in favor of #4677 to merge with latest master.