@ai-ecoverse/wasi-zig (with LLVM 21)

Zig 0.16.0 for slicc, built for wasm32-wasi with LLVM 21.1.8, clang and lld.

• zig build-exe / run / test / build, -ofmt=c, all optimize modes, with LLVM's optimizer for ReleaseFast / ReleaseSmall / ReleaseSafe.
• zig cc / zig c++ for wasm32-wasi. wasi-libc, libc++ and Zig's runtimes (compiler_rt, ubsan_rt, zigc) ship prebuilt for the baseline CPU; another CPU or mode (e.g. -mcpu=generic+simd128) builds wasi-libc from its C sources, in the optional @ai-ecoverse/wasi-zig-libc-src package (ipk install @ai-ecoverse/wasi-zig-libc-src).
• Backends: Debug builds of pure-Zig wasm32 code use Zig's self-hosted wasm backend (fast compiles, as in the no-LLVM package); Release modes, programs that link libc and C/C++ sources use LLVM. -fllvm / -fno-llvm (or .use_llvm on a compile step) override that per build.
• Targets: wasm32 / wasm64 only (the LLVM inside has the WebAssembly target); clang's resource headers are trimmed to the ones wasm uses.
• Runs with real threads under slicc (LLVM's thread pool, wasi-threads).
• @cImport and zig translate-c work (since 0.16.0-18, homescoop#1061). The first use compiles the translate-c tool into the cache, which takes a while.
• zig c++ for wasm32-wasi compiles with -fno-exceptions by default (since 0.16.0-18, homescoop#1062): the bundled libc++ has no exception support, as with wasi-sdk's clang. So code with throw or try doesn't compile ("cannot use 'throw' with exceptions disabled"), and an exception libc++ itself throws (std::map::at out of range, a failed new) aborts the program. -fexceptions turns them back on, and the link then fails (__cxa_throw undefined).

LLVM is Apache-2.0 WITH LLVM-exception (LICENSE-LLVM.TXT); Zig is MIT (LICENSE).