commit 3ef33e756a65484a17abb95ef0d4133f80c014b1
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Nov 4 12:45:32 2020

    libstdc++: Document istreambuf_iterator base class change [PR 92285]
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/92285
            * doc/xml/manual/evolution.xml: Document change to base class.
            * doc/html/manual/api.html: Regenerate.

diff --git a/libstdc++-v3/doc/xml/manual/evolution.xml b/libstdc++-v3/doc/xml/manual/evolution.xml
index 38f11b0300d4..55b8903baff5 100644
--- a/libstdc++-v3/doc/xml/manual/evolution.xml
+++ b/libstdc++-v3/doc/xml/manual/evolution.xml
@@ -972,6 +972,15 @@ now defaults to zero.
   be used instead.
 </para>
 
+<para>
+  The type of the <classname>std::iterator</classname> base class of
+  <classname>std::istreambuf_iterator</classname> was changed to be
+  consistent for all <option>-std</option> modes.
+  Before GCC 10.1 the base class had one type in C++98 mode and a
+  different type in C++11 and later modes. The type in C++98 mode
+  was changed to be the same as for C++11 and later.
+</para>
+
 <para>
   Experimental C++2a support improved, with new headers
   <filename class="headerfile">&lt;concepts&gt;</filename>,