[wwwdocs, pushed] Document dependency changes for libstdc++ header

[Jonathan Wakely]

Pushed to wwwdocs.

---
 htdocs/gcc-15/porting_to.html | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/htdocs/gcc-15/porting_to.html b/htdocs/gcc-15/porting_to.html
index 2bc0d4e5..b9b2efc7 100644
--- a/htdocs/gcc-15/porting_to.html
+++ b/htdocs/gcc-15/porting_to.html
@@ -153,6 +153,9 @@ may need to be included explicitly when compiling with GCC 
15:
   and <code>&lt;cstdint&gt;</code>
   (for <code>std::int8_t</code>, <code>std::int32_t</code> etc.)
 </li>
+<li> <code>&lt;ostream&gt;</code>
+(for <code>std::endl</code>, <code>std::flush</code> etc.)
+</li>
 </ul>
 
 <h3 id="deprecated-headers">Deprecated headers</h3>
-- 
2.47.1