iproute2: fix static build with uClibc

iproute2: fix static build with uClibc

Version 4.13 added a local definition of strlcpy(). This clashes with
the uClibc provided one when linking statically. Add a patch that
detects libc provided strlcpy(), and avoids the multiple definition.

Fixes:
http://autobuild.buildroot.net/results/f34/f34684dcdb47938a3da8b00c8b29000cc23b4e3d/
http://autobuild.buildroot.net/results/a01/a01c5775945f5ffe75451722b676fc93333a0f14/
http://autobuild.buildroot.net/results/0ee/0eeab1a0ca943f9a035a0d458ddf9cc210bc87f4/

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>