in6: fix conflict with glibc

Resolve conflicts between glibc definition of IPV6 socket options
and those defined in Linux headers. Looks like earlier efforts to
solve this did not cover all the definitions.

It resolves warnings during iproute2 build.
Please consider for stable as well.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h
index 74a2a17..79b12b0 100644
--- a/include/uapi/linux/in6.h
+++ b/include/uapi/linux/in6.h
@@ -149,7 +149,7 @@
 /*
  *	IPV6 socket options
  */
-
+#if __UAPI_DEF_IPV6_OPTIONS
 #define IPV6_ADDRFORM		1
 #define IPV6_2292PKTINFO	2
 #define IPV6_2292HOPOPTS	3
@@ -196,6 +196,7 @@
 
 #define IPV6_IPSEC_POLICY	34
 #define IPV6_XFRM_POLICY	35
+#endif
 
 /*
  * Multicast: