document DUK_OPT_FUNC_NONSTD_SOURCE_PROPERTY

website/guide/compiling.html

@@ -211,6 +211,13 @@ The table below summarizes the available options, in no particular order:</p>
     description of the property.  This feature disables tail call support.</td>
 </tr>
 <tr>
+<td class="definename">DUK_OPT_FUNC_NONSTD_SOURCE_PROPERTY</td>
+<td>Add a non-standard <code>source</code> property to function instances.
+    This allows function <code>toString()</code> to print out the actual
+    function source.  The property is disabled by default because it increases
+    memory footprint.</td>
+</tr>
+<tr>
 <td class="definename">DUK_OPT_NO_ARRAY_SPLICE_NONSTD_DELCOUNT</td>
 <td>For better compatibility with existing code, <code>Array.prototype.splice()</code>
     has non-standard behavior by default when the second argument (deleteCount)