api: fix compatibility of linux/in.h with netinet/in.h

u
This fixes breakage to iproute2 build with recent kernel headers
caused by:
   commit a263653ed798216c0069922d7b5237ca49436007
   Author: Pablo Neira Ayuso <pablo@netfilter.org>
   Date:   Wed Jun 17 10:28:27 2015 -0500

   netfilter: don't pull include/linux/netfilter.h from netns headers

The issue is that definitions in linux/in.h overlap with those
in netinet/in.h. This patch solves this by introducing the same
mechanism as was used to solve the same problem with linux/in6.h

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h
index fa673e9..7d024ce 100644
--- a/include/uapi/linux/libc-compat.h
+++ b/include/uapi/linux/libc-compat.h
@@ -56,6 +56,13 @@
 
 /* GLIBC headers included first so don't define anything
  * that would already be defined. */
+#define __UAPI_DEF_IN_ADDR		0
+#define __UAPI_DEF_IN_IPPROTO		0
+#define __UAPI_DEF_IN_PKTINFO		0
+#define __UAPI_DEF_IP_MREQ		0
+#define __UAPI_DEF_SOCKADDR_IN		0
+#define __UAPI_DEF_IN_CLASS		0
+
 #define __UAPI_DEF_IN6_ADDR		0
 /* The exception is the in6_addr macros which must be defined
  * if the glibc code didn't define them. This guard matches
@@ -78,6 +85,13 @@
 /* Linux headers included first, and we must define everything
  * we need. The expectation is that glibc will check the
  * __UAPI_DEF_* defines and adjust appropriately. */
+#define __UAPI_DEF_IN_ADDR		1
+#define __UAPI_DEF_IN_IPPROTO		1
+#define __UAPI_DEF_IN_PKTINFO		1
+#define __UAPI_DEF_IP_MREQ		1
+#define __UAPI_DEF_SOCKADDR_IN		1
+#define __UAPI_DEF_IN_CLASS		1
+
 #define __UAPI_DEF_IN6_ADDR		1
 /* We unconditionally define the in6_addr macros and glibc must
  * coordinate. */
@@ -103,6 +117,14 @@
  * that we need. */
 #else /* !defined(__GLIBC__) */
 
+/* Definitions for in.h */
+#define __UAPI_DEF_IN_ADDR		1
+#define __UAPI_DEF_IN_IPPROTO		1
+#define __UAPI_DEF_IN_PKTINFO		1
+#define __UAPI_DEF_IP_MREQ		1
+#define __UAPI_DEF_SOCKADDR_IN		1
+#define __UAPI_DEF_IN_CLASS		1
+
 /* Definitions for in6.h */
 #define __UAPI_DEF_IN6_ADDR		1
 #define __UAPI_DEF_IN6_ADDR_ALT		1