moved all crates into seperate folder + related path fixes

crates/wasi-libc-sys/src/lib.rs

@@ -0,0 +1,18 @@
+// Rust's libc crate doesn't support Wasm, so we provide an implementation from Zig
+// We define Rust signatures here as we need them, rather than trying to cover all of libc
+#[cfg(target_family = "wasm")]
+use core::ffi::c_void;
+#[cfg(target_family = "wasm")]
+extern "C" {
+    pub fn malloc(size: usize) -> *mut c_void;
+    pub fn free(p: *mut c_void);
+    pub fn realloc(p: *mut c_void, size: usize) -> *mut c_void;
+    pub fn memcpy(dst: *mut c_void, src: *mut c_void, n: usize) -> *mut c_void;
+    pub fn memset(dst: *mut c_void, ch: i32, n: usize) -> *mut c_void;
+}
+
+// Tell users of this crate where to find the Wasm .a file
+// If a non-Wasm target is using this crate, we assume it is a build script that wants to emit Wasm
+// For Wasm target, it won't ever be used, but we expose it just to keep things simple
+mod generated;
+pub use generated::{WASI_COMPILER_RT_PATH, WASI_LIBC_PATH};