Add 0.19.0 API methods where appropriate

[plicease]

The new header file changes are mostly comments, but:

• funcref functions

+/**
+ * \brief Creates a new `funcref` value referencing `func`.
+ *
+ * Create a `funcref` value that references `func` and writes it to `funcrefp`.
+ *
+ * Gives ownership fo the `funcref` value written to `funcrefp`.
+ *
+ * Both `func` and `funcrefp` must not be NULL.
+ */
+WASM_API_EXTERN void wasmtime_func_as_funcref(const wasm_func_t* func, wasm_val_t* funcrefp);
+
+/**
+ * \brief Get the `wasm_func_t*` referenced by the given `funcref` value.
+ *
+ * Gets an owning handle to the `wasm_func_t*` that the given `funcref` value is
+ * referencing. Returns NULL if the value is not a `funcref`, or if the value is
+ * a null function reference.
+ *
+ * The `val` pointer must not be NULL.
+ */
+WASM_API_EXTERN own wasm_func_t* wasmtime_funcref_as_func(const wasm_val_t* val);

• exit_status method

+/**
+ * \brief Attempts to extract a WASI-specific exit status from this trap.
+ *
+ * Returns `true` if the trap is a WASI "exit" trap and has a return status. If
+ * `true` is returned then the exit status is returned through the `status`
+ * pointer. If `false` is returned then this is not a wasi exit trap.
+ */
+WASM_API_EXTERN bool wasmtime_trap_exit_status(const wasm_trap_t*, int *status);

• update module constructor

 WASM_API_EXTERN own wasmtime_error_t *wasmtime_module_new(
-    wasm_store_t *store,
+    wasm_engine_t *engine,
     const wasm_byte_vec_t *binary,
     own wasm_module_t **ret
 );

• externref functions

+/**
+ * \brief Create a new `externref` value.
+ *
+ * Creates a new `externref` value wrapping the provided data, and writes it to
+ * `valp`.
+ *
+ * This function does not take an associated finalizer to clean up the data when
+ * the reference is reclaimed. If you need a finalizer to clean up the data,
+ * then use #wasmtime_externref_new_with_finalizer.
+ *
+ * Gives ownership of the newly created `externref` value.
+ */
+WASM_API_EXTERN void wasmtime_externref_new(own void *data, wasm_val_t *valp);
+
+/**
+ * \brief A finalizer for an `externref`'s wrapped data.
+ *
+ * A finalizer callback to clean up an `externref`'s wrapped data after the
+ * `externref` has been reclaimed. This is an opportunity to run destructors,
+ * free dynamically allocated memory, close file handles, etc.
+ */
+typedef void (*wasmtime_externref_finalizer_t)(void*);
+
+/**
+ * \brief Create a new `externref` value with a finalizer.
+ *
+ * Creates a new `externref` value wrapping the provided data, and writes it to
+ * `valp`.
+ *
+ * When the reference is reclaimed, the wrapped data is cleaned up with the
+ * provided finalizer. If you do not need to clean up the wrapped data, then use
+ * #wasmtime_externref_new.
+ *
+ * Gives ownership of the newly created `externref` value.
+ */
+WASM_API_EXTERN void wasmtime_externref_new_with_finalizer(
+    own void *data,
+    wasmtime_externref_finalizer_t finalizer,
+    wasm_val_t *valp
+);
+
+/**
+ * \brief Get an `externref`'s wrapped data
+ *
+ * If the given value is a reference to a non-null `externref`, writes the
+ * wrapped data that was passed into #wasmtime_externref_new or
+ * #wasmtime_externref_new_with_finalizer when creating the given `externref` to
+ * `datap`, and returns `true`.
+ *
+ * If the value is a reference to a null `externref`, writes `NULL` to `datap`
+ * and returns `true`.
+ *
+ * If the given value is not an `externref`, returns `false` and leaves `datap`
+ * unmodified.
+ *
+ * Does not take ownership of `val`. Does not give up ownership of the `void*`
+ * data written to `datap`.
+ *
+ * Both `val` and `datap` must not be `NULL`.
+ */
+WASM_API_EXTERN bool wasmtime_externref_data(wasm_val_t* val, void** datap);
+

• get_one_by_name method.

[plicease]

Missed this one:

+/**
+ * \brief Loads an item by name from this linker.
+ *
+ * \param linker the linker to load from
+ * \param module the name of the module to get
+ * \param name the name of the field to get
+ * \param item where to store the extracted item
+ *
+ * \return An error is returned if the item isn't defined or has more than one
+ * definition, or `NULL` is returned and `item` is filled in otherwise.
+ */
+WASM_API_EXTERN own wasmtime_error_t* wasmtime_linker_get_one_by_name(
+    const wasmtime_linker_t *linker,
+    const wasm_name_t *module,
+    const wasm_name_t *name,
+    own wasm_extern_t **item
+);

🎉