Some warnings are considered errors

I tried to compile the driver for the wireless USB-key on my Arch (3.18.14-2 custom kernel), while I came across this error: cc1: some warnings being treated as errors

. I checked out a few tips on how to remove this warning message where people said it needs to be removed -Werror

in the Makefile. However, I have checked and this file does not -Werror

. Any advice?