Remove usage of Features from wasmtime::Config API (#763)

Instead expose a number of boolean accessors which doesn't require users
to construct a foreign `Features` type and allows us to decouple the API
of the `wasmtime` crate from the underlying implementation detail.

crates/misc/rust/Cargo.toml

@@ -16,7 +16,6 @@ doctest = false
 
 [dependencies]
 wasmtime-interface-types = { path = "../../interface-types" }
-wasmtime-jit = { path = "../../jit" }
 wasmtime-rust-macro = { path = "./macro" }
 wasmtime-wasi = { path = "../../wasi" }
 wasmtime = { path = "../../api" }

crates/misc/rust/macro/src/lib.rs

@@ -51,12 +51,7 @@ fn generate_load(item: &syn::ItemTrait) -> syn::Result<TokenStream> {
             use #root::wasmtime::{HostRef, Config, Extern, Engine, Store, Instance, Module};
             use #root::anyhow::{bail, format_err};
 
-            let mut config = Config::new();
-            config.features(#root::wasmtime_jit::Features {
-                multi_value: true,
-                ..Default::default()
-            });
-            let engine = Engine::new(&config);
+            let engine = Engine::new(Config::new().wasm_multi_value(true));
             let store = HostRef::new(Store::new(&engine));
             let global_exports = store.borrow().global_exports().clone();
 

crates/misc/rust/src/lib.rs

@@ -6,7 +6,6 @@ pub mod __rt {
     pub use anyhow;
     pub use wasmtime;
     pub use wasmtime_interface_types;
-    pub use wasmtime_jit;
     pub use wasmtime_wasi;
 
     use std::convert::{TryFrom, TryInto};