commit cb43bb0d68f001fc3d6e054d712ab8794b5fd1de
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date:   Tue Jan 6 16:13:19 2015 -0800

    in.h: Coordinate in6_pktinfo and ip6_mtuinfo for kernel and glibc [BZ #15850]
    
    Similarly to what we did for in6_addr, we need a macro
    to guard in6_pktinfo and ip6_mtuinfo too.
    
    Cc: Carlos O'Donell <carlos@redhat.com>
    Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

diff --git a/inet/netinet/in.h b/inet/netinet/in.h
index bf3c8b1..f541c58 100644
--- a/inet/netinet/in.h
+++ b/inet/netinet/in.h
@@ -530,6 +530,7 @@ extern int bindresvport6 (int __sockfd, struct sockaddr_in6 *__sock_in)
 #ifdef __USE_GNU
 struct cmsghdr;			/* Forward declaration.  */
 
+#ifndef __USE_KERNEL_IPV6_DEFS
 /* IPv6 packet information.  */
 struct in6_pktinfo
   {
@@ -543,7 +544,7 @@ struct ip6_mtuinfo
     struct sockaddr_in6 ip6m_addr; /* dst address including zone ID */
     uint32_t ip6m_mtu;		   /* path MTU in host byte order */
   };
-
+#endif /* !__USE_KERNEL_IPV6_DEFS */
 
 /* Obsolete hop-by-hop and Destination Options Processing (RFC 2292).  */
 extern int inet6_option_space (int __nbytes)
diff --git a/sysdeps/unix/sysv/linux/bits/in.h b/sysdeps/unix/sysv/linux/bits/in.h
index b80a27f..b1d2cf6 100644
--- a/sysdeps/unix/sysv/linux/bits/in.h
+++ b/sysdeps/unix/sysv/linux/bits/in.h
@@ -23,10 +23,10 @@
 
 /* If the application has already included linux/in6.h from a linux-based
    kernel then we will not define the IPv6 IPPROTO_* defines, in6_addr (nor the
-   defines), sockaddr_in6, or ipv6_mreq.  The ABI used by the linux-kernel and
-   glibc match exactly.  Neither the linux kernel nor glibc should break this
-   ABI without coordination.  */
-#ifdef _UAPI_LINUX_IN6_H
+   defines), sockaddr_in6, or ipv6_mreq. Same for in6_ptkinfo or ip6_mtuinfo
+   in linux/ipv6.h. The ABI used by the linux-kernel and glibc match exactly.
+   Neither the linux kernel nor glibc should break this ABI without coordination.  */
+#if defined _UAPI_LINUX_IN6_H || defined _UAPI_IPV6_H
 /* This is not quite the same API since the kernel always defines s6_addr16 and
    s6_addr32. This is not a violation of POSIX since POSIX says "at least the
    following member" and that holds true.  */