[committed] wwwdocs: gcc-14: Add release notes for C23 features

[Joseph Myers <josmyers@redhat.com>]

Add release notes for C23 features added in GCC 14.  This doesn't
cover any non-C23 new C features; any such features should also have
release notes added.

diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html
index 934cd1ad..045893cf 100644
--- a/htdocs/gcc-14/changes.html
+++ b/htdocs/gcc-14/changes.html
@@ -206,6 +206,31 @@ a work-in-progress.</p>
 
 <!-- <h3 id="c-family">C family</h3> -->
 
+<h3 id="c">C</h3>
+
+<ul>
+  <li>Some more C23 features have been implemented:
+    <ul>
+      <li>Bit-precise integer types (<code>_BitInt (<i>N</i>)</code>
+      and <code>unsigned _BitInt (<i>N</i>)</code>): integer types with
+      a specified number of bits.  These are only supported on
+      IA-32/x86-64 at present.</li>
+      <li>Structure, union and enumeration types may be defined more
+      than once in the same scope with the same contents and the same
+      tag; if such types are defined with the same contents and the
+      same tag in different scopes, the types are compatible.</li>
+      <li>The <code>&lt;stdckdint.h&gt;</code> header for checked
+      integer arithmetic.</li>
+    </ul>
+  </li>
+  <li>In addition to those C23 features, there are new command-line
+  options <code>-std=c23</code>, <code>-std=gnu23</code>
+  and <code>-Wc11-c23-compat</code>.  These are equivalent to the
+  previous options <code>-std=c2x</code>, <code>-std=gnu2x</code>
+  and <code>-Wc11-c2x-compat</code>, which are deprecated but remain
+  supported.</li>
+</ul>
+
 <h3 id="cxx">C++</h3>
 
 <ul>

-- 
Joseph S. Myers
josmyers@redhat.com