Repair compilation for Visual Studio 2005.

I applied the same changes manually to VS7.1 and VC6 files; completely untested.

(Christian, don't try too hard merging this change into py3k.
It will be easier to do the same work again on the branch)
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 13354d0..e956831 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -5230,8 +5230,12 @@
 	PyModule_AddIntConstant(m, "RCVALL_OFF", RCVALL_OFF);
 	PyModule_AddIntConstant(m, "RCVALL_ON", RCVALL_ON);
 	PyModule_AddIntConstant(m, "RCVALL_SOCKETLEVELONLY", RCVALL_SOCKETLEVELONLY);
+#ifdef RCVALL_IPLEVEL
 	PyModule_AddIntConstant(m, "RCVALL_IPLEVEL", RCVALL_IPLEVEL);
+#endif
+#ifdef RCVALL_MAX
 	PyModule_AddIntConstant(m, "RCVALL_MAX", RCVALL_MAX);
+#endif
 #endif /* _MSTCPIP_ */
 
 	/* Initialize gethostbyname lock */