Build failure if defined IP_PKTINFO but missing ipi_spec_dst in struct in_pktinfo

[OBATA Akio]

In ngx_sendmsg() of src/os/unix/ngx_udp_sendmsg_chain.c,
if IP_PKTINFO is available for setsockopt (NGX_HAVE_PKTINFO),
in_pktinfo.ipi_spec_dst is used unconditionally.

But it is missing for NetBSD-7.1, so I cannot build nginx-1.13.0.

[Roman Arutyunyan]

Thanks for reporting this.
Please try the attached patch.

[OBATA Akio]

Yes, it resolve the build failure, but NGX_HAVE_IP_PKTINFO is also used in other places without using in_pktinfo.ipi_spec_dst.

From manual of NetBSD ip(4) and Windows Sockets 2 (used on Cygwin), ipi_addr member of
in_pktinfo is usable for both source and destnation depending on its usage.

[Roman Arutyunyan]

As for NetBSD, the manual seems to be wrong.
IP_PKTINFO is in fact only supported for recvmsg().

​http://gnats.netbsd.org/48280

[Roman Arutyunyan]

The patch was committed:
​http://hg.nginx.org/nginx/rev/716852cce913