um: add missing declaration of 'getrlimit()' and friends

commit fdfa4c952844fce881df8c76de9c7180cbe913ab upstream.
commit 809d29070ffcf808e86f37e9e1971cd2b8caaf49 in stable/3.4.y.

arch/um/os-Linux/start_up.c: In function 'check_coredump_limit':
arch/um/os-Linux/start_up.c:338:16: error: storage size of 'lim' isn't known
arch/um/os-Linux/start_up.c:339:2: error: implicit declaration of function 'getrlimit' [-Werror=implicit-function-declaration]

Bug: 15413527
Change-Id: I81d930d9636bfc95e0c2140f2901628dc609df79
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
CC: Jeff Dike <jdike@addtoit.com>
CC: Richard Weinberger <richard@nod.at>
CC: Al Viro <viro@zeniv.linux.org.uk>
CC: user-mode-linux-devel@lists.sourceforge.net
CC: user-mode-linux-user@lists.sourceforge.net
CC: linux-kernel@vger.kernel.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: ipv6: Add a sysctl to make optimistic addresses useful candidates

Add a sysctl that causes an interface's optimistic addresses
to be considered equivalent to other non-deprecated addresses
for source address selection purposes.  Preferred addresses
will still take precedence over optimistic addresses, subject
to other ranking in the source address selection algorithm.

This is useful where different interfaces are connected to
different networks from different ISPs (e.g., a cell network
and a home wifi network).

The current behaviour complies with RFC 3484/6724, and it
makes sense if the host has only one interface, or has
multiple interfaces on the same network (same or cooperating
administrative domain(s), but not in the multiple distinct
networks case.

For example, if a mobile device has an IPv6 address on an LTE
network and then connects to IPv6-enabled wifi, while the wifi
IPv6 address is undergoing DAD, IPv6 connections will try use
the wifi default route with the LTE IPv6 address, and will get
stuck until they time out.

Also, because optimistic nodes can receive frames, issue
an RTM_NEWADDR as soon as DAD starts (with the IFA_F_OPTIMSTIC
flag appropriately set).  A second RTM_NEWADDR is sent if DAD
completes (the address flags have changed), otherwise an
RTM_DELADDR is sent.

Also: add an entry in ip-sysctl.txt for optimistic_dad.

[backport of net-next 7fd2561e4ebdd070ebba6d3326c4c5b13942323f]

Signed-off-by: Erik Kline <ek@google.com>
Acked-by: Lorenzo Colitti <lorenzo@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Bug: 17769720
Change-Id: I440a9b8c788db6767d191bbebfd2dff481aa9e0d