[new package] wasi-libc

[ArchGuyWu]

wasi-libc is a libc for WebAssembly programs built on top of WASI system calls. It provides a wide array of POSIX-compatible C APIs, including support for standard I/O, file I/O, filesystem manipulation, memory management, time, string, environment variables, program startup, and many other APIs.

[ArchGuyWu]

It built successfully in CLANG64, but not in UCRT64 and MINGW64. In UCRT64 and MINGW64, AR is set as gcc, and I'm unsure why.

In CLANG64:

for name in m rt pthread crypt util xnet resolv; do \
      llvm-ar crs "/C/_/B/src/wasi-libc/sysroot/lib/wasm32-wasi/lib${name}.a"; \
done

In UCRT64 and MINGW64:

for name in m rt pthread crypt util xnet resolv; do \
      gcc crs "/C/_/B/src/wasi-libc/sysroot/lib/wasm32-wasi/lib${name}.a"; \
done

[ArchGuyWu]

I've opened an issue on the wasi-libc repo: WebAssembly/wasi-libc#523

[ArchGuyWu]

Now we're ready to add package rust-wasm.

[ArchGuyWu]

I'll try to add package rust-wasm by myself, so close this for now.