PR libstdc++/81835 fix broken URLs in libstdc++ docs

	PR libstdc++/81835
	* doc/xml/manual/extensions.xml: Replace unstable URL.
	* doc/html/manual/ext_demangling.html: Regenerate.
	* libsupc++/cxxabi.h (__cxa_demangle): Fix broken URL.

From-SVN: r252066

libstdc++-v3/ChangeLog

 2017-09-13  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/81835
+	* doc/xml/manual/extensions.xml: Replace unstable URL.
+	* doc/html/manual/ext_demangling.html: Regenerate.
+	* libsupc++/cxxabi.h (__cxa_demangle): Fix broken URL.
+
 	* include/bits/allocated_ptr.h (__allocated_ptr::get): Use
 	__to_address.
 	(__allocated_ptr::_S_raw_ptr): Remove.

libstdc++-v3/doc/html/manual/ext_demangling.html

@@ -7,7 +7,7 @@
     original C++ source identifiers is called
     <span class="quote">“<span class="quote">demangling.</span>”</span>
   </p><p>
-    If you have read the <a class="link" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01115.html" target="_top">source
+    If you have read the <a class="link" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/namespaces.html" target="_top">source
     documentation for <code class="code">namespace abi</code></a> then you are
     aware of the cross-vendor C++ ABI in use by GCC.  One of the
     exposed functions is used for demangling,

libstdc++-v3/doc/xml/manual/extensions.xml

@@ -502,7 +502,7 @@ get_temporary_buffer(5, (int*)0);
     <quote>demangling.</quote>
   </para>
   <para>
-    If you have read the <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01115.html">source
+    If you have read the <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/namespaces.html">source
     documentation for <code>namespace abi</code></link> then you are
     aware of the cross-vendor C++ ABI in use by GCC.  One of the
     exposed functions is used for demangling,

libstdc++-v3/libsupc++/cxxabi.h

@@ -182,7 +182,7 @@ namespace __cxxabiv1
    *  with GNU extensions. For example, this function is used in
    *  __gnu_cxx::__verbose_terminate_handler.
    *
-   *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt12ch39.html
+   *  See https://gcc.gnu.org/onlinedocs/libstdc++/manual/ext_demangling.html
    *  for other examples of use.
    *
    *  @note The same demangling functionality is available via