iproute2: don't optimize unused routines

[Yegor Yefremov]

Hi

I've posted this patch to AOSP:
https://android-review.googlesource.com/#/c/34240/

Could you please review it and tell, what you think about it? As far
as I know you have boards with CAN interface like Freescale ones. How
do you test CAN interface on them?

I've started a discussion on socketcan mailing list:
http://comments.gmane.org/gmane.linux.can/852. It turns out to be some
projects suitable for Android. I'm evaluating them and will report my
results. But I would really like to see my patch commited to AOSP or
alternative version, that fixes the problem without diverging from
main line iproute2 code too much.

Regards,
Yegor