Updated changes.xml doc

users_guide/changes.xml

@@ -2,6 +2,20 @@
 <chapter id="changes">
   <title>Change History</title>
 
+  <simplesect>
+    <title>Changes For Version 1.6.20 (Unreleased)</title>
+
+    <itemizedlist mark="bullet">
+      <listitem>
+        <para>The previous release of FXRuby couldn't be built from source against Ruby 1.9.1 final
+        due to a change in some of the file-related utility libraries
+        (see <ulink
+        url="http://rubyforge.org/tracker/index.php?func=detail&amp;aid=23786&amp;group_id=300&amp;atid=1223">RubyForge
+        Bug #23786</ulink>). This problem has been corrected.</para>
+      </listitem>
+    </itemizedlist>
+  </simplesect>
+
   <simplesect>
     <title>Changes For Version 1.6.19 (March 6, 2009)</title>
 
@@ -1986,4 +2000,4 @@
       </listitem>
     </itemizedlist>
   </simplesect>
-</chapter>
+</chapter>
\ No newline at end of file