build kernel on RPI2 errors

[Tim Kientzle]

> On Oct 4, 2015, at 8:35 PM, Stefan Parvu <sparvu at kronometrix.org> wrote:
> 
> cc: error: unable to execute command: Killed
> cc: error: clang frontend command failed due to signal (use -v to see
> invocation)

I wonder if this error message could be any better?
It's such a common issue on these small-memory systems.

Is it possible for 'cc' to detect whether clang died
due to an out-of-memory condition and print out
a slightly more detailed message in that case?

Tim