add wat2wasm note to readme
@@ -59,6 +59,11 @@ You can then run tests with::
./test-all.sh
+You may need to install the *wat2wasm* tool from the `wabt
+<https://github.com/WebAssembly/wabt>`_ project in order to run all of the
+WebAssembly tests. Tests requiring wat2wasm are ignored if the tool is not
+installed.
+
Building the documentation
--------------------------
