Initial reorg.

This is largely the same as #305, but updated for the current tree.

crates/wasi-common/src/lib.rs

@@ -0,0 +1,42 @@
+#![deny(
+    // missing_docs,
+    trivial_numeric_casts,
+    unused_extern_crates,
+    unstable_features
+)]
+#![warn(unused_import_braces)]
+#![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../clippy.toml")))]
+#![cfg_attr(feature = "cargo-clippy", allow(clippy::new_without_default))]
+#![cfg_attr(
+    feature = "cargo-clippy",
+    warn(
+        clippy::float_arithmetic,
+        clippy::mut_mut,
+        clippy::nonminimal_bool,
+        clippy::option_map_unwrap_or,
+        clippy::option_map_unwrap_or_else,
+        clippy::unicode_not_nfc,
+        clippy::use_self
+    )
+)]
+
+mod ctx;
+mod error;
+mod fdentry;
+mod helpers;
+mod hostcalls_impl;
+mod sys;
+#[macro_use]
+mod macros;
+pub mod fs;
+mod host;
+pub mod hostcalls;
+mod memory;
+pub mod wasi;
+pub mod wasi32;
+
+pub use ctx::{WasiCtx, WasiCtxBuilder};
+pub use sys::preopen_dir;
+
+pub type Error = error::Error;
+pub(crate) type Result<T> = std::result::Result<T, Error>;