Build: Find GNUARM compiler via find_program()

This makes it work better on Windows, which needs .exe in the filename,
and also makes it easier to detect errors with the toolchain.

Change-Id: Ic6492b6cea23b81bf521daa9f2953544f012b607
Signed-off-by: Øyvind Rønningstad <oyvind.ronningstad@nordicsemi.no>
1 file changed