Issue #8235: _socket: Add the constant ``SO_SETFIB``.  SO_SETFIB is
a socket option available on FreeBSD 7.1 and newer.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index d44a691..901cb7d 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -4779,6 +4779,9 @@
 #ifdef	SO_TYPE
 	PyModule_AddIntConstant(m, "SO_TYPE", SO_TYPE);
 #endif
+#ifdef SO_SETFIB
+    PyModule_AddIntConstant(m, "SO_SETFIB", SO_SETFIB);
+#endif
 
 	/* Maximum number of connections for "listen" */
 #ifdef	SOMAXCONN