Update wasi-libc to d03829489904d38c624f6de9983190f1e5e7c9c5
Most notable improvements include realpath and stubs for statvfs, chmod, etc.
Other changes are for WASI 0.2 which is going to be painful to support since 3rd party tools written in Rust may become necessary in addition to LLVM (https://github.com/WebAssembly/wasi-sdk/pull/402)
This also removes junk we were shipping but irrelevant to webassembly.
10KLoc reduce, feel so good
Added the wasi-libc libdl shim, so that tools such as py2wasm can use zig cc.
man. wasi-libc kinda sucks. how about we provide libc via zig code instead?
wasi-libc is horrible. And it's getting worse with the wasi preview 2 bits.
But rewriting it in Zig would be a lot of work.