Recognize "wasi_unstable_preview0" in addition to "wasi_unstable".

src/bin/wasmtime.rs

@@ -316,6 +316,10 @@ fn rmain() -> Result<(), Error> {
         "wasi_unstable".to_owned(),
         Instance::from_handle(store.clone(), wasi)?,
     );
+    module_registry.insert(
+        "wasi_unstable_preview0".to_owned(),
+        Instance::from_handle(store.clone(), wasi)?,
+    );
 
     // Load the preload wasm modules.
     for filename in &args.flag_preload {

wasmtime-wasi-c/js-polyfill/polyfill.c

@@ -22,7 +22,10 @@ void handleFiles(void) {
         __builtin_trap();
 
     EM_ASM(" \
-        const imports = { wasi_unstable: WASIPolyfill }; \
+        const imports = {\
+            wasi_unstable: WASIPolyfill, \
+            wasi_unstable_preview0: WASIPolyfill \
+        }; \
         let file = document.getElementById('input').files[0]; \
         let file_with_mime_type = file.slice(0, file.size, 'application/wasm'); \
         let response = new Response(file_with_mime_type); \