Vendor dependencies

Let's see how I like this workflow.

vendor/wasm-bindgen-macro/ui-tests/invalid-items.stderr

@@ -0,0 +1,59 @@
+error: can only #[wasm_bindgen] public functions
+ --> $DIR/invalid-items.rs:4:1
+  |
+4 | fn foo() {}
+  | ^^^^^^^^^^^
+
+error: can only #[wasm_bindgen] non-const functions
+ --> $DIR/invalid-items.rs:7:5
+  |
+7 | pub const fn foo2() {}
+  |     ^^^^^
+
+error: structs with #[wasm_bindgen] cannot have lifetime or type parameters currently
+  --> $DIR/invalid-items.rs:10:11
+   |
+10 | struct Foo<T>(T);
+   |           ^^^
+
+error: cannot import mutable globals yet
+  --> $DIR/invalid-items.rs:14:12
+   |
+14 |     static mut FOO: u32;
+   |            ^^^
+
+error: can't #[wasm_bindgen] variadic functions
+  --> $DIR/invalid-items.rs:16:25
+   |
+16 |     pub fn foo3(x: i32, ...);
+   |                         ^^^
+
+error: only foreign mods with the `C` ABI are allowed
+  --> $DIR/invalid-items.rs:20:8
+   |
+20 | extern "system" {
+   |        ^^^^^^^^
+
+error: can't #[wasm_bindgen] functions with lifetime or type parameters
+  --> $DIR/invalid-items.rs:24:12
+   |
+24 | pub fn foo4<T>() {}
+   |            ^^^
+
+error: can't #[wasm_bindgen] functions with lifetime or type parameters
+  --> $DIR/invalid-items.rs:26:12
+   |
+26 | pub fn foo5<'a>() {}
+   |            ^^^^
+
+error: can't #[wasm_bindgen] functions with lifetime or type parameters
+  --> $DIR/invalid-items.rs:28:12
+   |
+28 | pub fn foo6<'a, T>() {}
+   |            ^^^^^^^
+
+error: #[wasm_bindgen] can only be applied to a function, struct, enum, impl, or extern block
+  --> $DIR/invalid-items.rs:31:1
+   |
+31 | trait X {}
+   | ^^^^^^^^^^