update emscripten compatibility info in guide

website/guide/compatibility.html

@@ -70,16 +70,14 @@ by Duktape.</p>
 
 <p><a href="https://github.com/kripken/emscripten">Emscripten</a> compiles
 C/C++ into Javascript.  Because Duktape is not a high performance engine,
-running large Emscripten-compiled program is probably not a good idea.
+running large Emscripten-compiled programs is probably not a good idea.
 Duktape is currently Emscripten compatible except for:</p>
 <ul>
 <li>There is one non-standard RegExp in the Emscripten output, causing
     a SyntaxError.  This is easy to fix manually.</li>
-<li>Duktape doesn't have typed arrays which need to be disabled with an
+<li>Duktape doesn't yet have typed arrays, so give <code>emcc</code> the
-    <code>emcc</code> option.  Without typed arrays Emscripten generated
+    option <code>-s USE_TYPED_ARRAYS=0</code> to disable their use.</li>
-    code will run quite slowly and memory inefficiently.</li>
+</ul>
-<li>The default total memory and total stack sizes need to be adjusted
-    with an <code>emcc</code> option.</li>
 
 <p>See 
 <a href="https://github.com/svaarala/duktape/blob/master/doc/emscripten-status.txt">emscripten-status.txt</a>