[wwwdocs] Update GCC5 changes.html

[Marek Polacek <polacek at redhat dot com>]

I've put together a few lines describing what I (except
-fsanitize=alignment) implemented for GCC 5.
It's the file wwwdocs/htdocs/gcc-5/changes.html.

Ok?

--- changes.html.mp	2014-08-13 12:21:57.059610612 +0200
+++ changes.html	2014-08-13 13:22:00.683597815 +0200
@@ -16,11 +16,53 @@
 
 <h2 id="general">General Optimizer Improvements</h2>
 
+  <ul>
+    <li>UndefinedBehaviorSanitizer gained a few new sanitization options:
+    <ul>
+      <li><code>-fsanitize=float-divide-by-zero</code>: detect floating-point
+	   division by zero;</li>
+      <li><code>-fsanitize=float-cast-overflow</code>: check that the result
+	   of floating-point type to integer conversion does not overflow;</li>
+      <li><code>-fsanitize=bounds</code>: enable instrumentation of array bounds
+	  and detect out-of-bounds accesses;</li>
+      <li><code>-fsanitize=alignment</code>: enable alignment checking, detect
+	  various misaligned objects.</li>
+    </ul>
+    </li>
+  </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">C</h3-->
+<h3 id="c-family">C family</h3>
+
+  <ul>
+    <li>A new <code>-Wswitch-bool</code> option has been added for the C and C++
+	compilers, which warns whenever a <code>switch</code> statement has an
+	index of boolean type.</li>
+    <li>A new <code>-Wlogical-not-parentheses</code> option has been added for the
+	C and C++ compilers, which warns about logical not used on the left hand
+	side operand of a comparison.</li>
+    <li>A new <code>-Wsizeof-array-argument</code> option has been added for the
+	C and C++ compilers, which warns when the <code>sizeof</code> operator is
+	applied to a parameter that is declared as an array in a function definition.
+  </ul>
+
+<h3 id="c">C</h3>
+
+  <ul>
+    <li>A new <code>-Wc90-c99-compat</code> option has been added to warn
+	about features not present in ISO C90, but present in ISO C99.</li>
+    <li>It is possible to disable warnings about conversions between pointers
+	that have incompatible types via a new warning option
+	<code>-Wno-incompatible-pointer-types</code>; warnings about implicit
+	incompatible integer to pointer and pointer to integer conversions via
+	a new warning option <code>-Wno-int-conversion</code>; and warnings about
+	qualifiers on pointers being discarded via a new warning option
+	<code>-Wno-discarded-qualifiers</code>.</li>
+    <li>The C front end now generates more precise caret diagnostics.</li>
+  </ul>
+
 <!-- h3 id="cxx">C++</h3-->
   <!-- h4 id="libstdcxx">Runtime Library (libstdc++)</h4-->
 <h3 id="fortran">Fortran</h3>

	Marek