Add IPV6_HDRINCL constant to the socket module

Author: Rosuav

Doc/library/socket.rst

@@ -482,6 +482,9 @@ The AF_* and SOCK_* constants are now :class:`AddressFamily` and
    .. versionchanged:: 3.14
       Added support for ``TCP_QUICKACK`` on Windows platforms when available.
 
+   .. versionchanged:: 3.15
+      ``IPV6_HDRINCL`` was added.
+
 
 .. data:: AF_CAN
           PF_CAN

Modules/socketmodule.c

@@ -8901,6 +8901,9 @@ socket_exec(PyObject *m)
 #ifdef IPV6_HOPLIMIT
     ADD_INT_MACRO(m, IPV6_HOPLIMIT);
 #endif
+#ifdef IPV6_HDRINCL
+    ADD_INT_MACRO(m, IPV6_HDRINCL);
+#endif
 #ifdef IPV6_HOPOPTS
     ADD_INT_MACRO(m, IPV6_HOPOPTS);
 #endif