[knc1]

@Hawhill: Very correct. I was typing in a hurry this morning.

Some toolchains are shipped with a 3-tuple name, some with a 4-tuple name with different implications for the trailing field when: "-eabi".

But I suspect that your first answer is the O.P.'s problem -
the include <sys/***> does not exist on a standalone tool chain (its standalone, no: "sys" toolchain).

We have both hosted and standalone toolchains in the DIY-KeK resource pool.
A build -56 and -57 as I recall, easy to pick the wrong one.
But since the O.P. shows a 3-tuple name - the O.P. is probably using a "Distro" tool chain and all bets are off on which one they are using.
Unless they do a: gcc -dump-machine for us.