[wwwdocs] Update changes.html

[Marek Polacek]

Ok to commit?

Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-6/changes.html,v
retrieving revision 1.3
diff -u -r1.3 changes.html
--- changes.html	6 May 2015 09:55:29 -0000	1.3
+++ changes.html	11 May 2015 14:44:38 -0000
@@ -16,15 +16,36 @@
 
 
 <!-- .................................................................. -->
-<!-- <h2 id="general">General Optimizer Improvements</h2> -->
-
+<h2 id="general">General Optimizer Improvements</h2>
+  <ul>
+    <li>UndefinedBehaviorSanitizer gained a new sanitization option:
+    <ul>
+      <li><code>-fsanitize=bounds-strict</code>: enables strict checking
+	  of array bounds.  In particular, it enables
+	  <code>-fsanitize=bounds</code> as well as instrumentation of
+	  flexible array member-like arrays.</li>
+    </ul>
+  </ul>
 
 <!-- .................................................................. -->
 <h2 id="languages">New Languages and Language specific improvements</h2>
 
 <!-- <h3 id="ada">Ada</h3> -->
 
-<!-- <h3 id="c-family">C family</h3> -->
+<h3 id="c-family">C family</h3>
+  <ul>
+    <li>A new command-line option <code>-Wshift-negative-value</code> has been
+	added for the C and C++ compilers, which warns about left shifting
+	a negative value.</li>
+  </ul>
+
+<h3 id="c">C</h3>
+  <ul>
+    <li>It is possible to disable warnings when an initialized field of
+	a structure or an union with side effects is being overridden when
+	using designated initializers via a new warning option
+	<code>-Woverride-init-side-effects</code>.</li>
+  </ul>
 
 <h3 id="cxx">C++</h3>
 

	Marek