Thanks for the quick reply.
./configure --prefix=/usr and it worked but produced this error:
ERROR: Kernel configuration is invalid.
include/generated/autoconf.h or include/config/auto.conf are missing.
Run 'make oldconfig && make prepare' on kernel src to fix it.
I'm unsure if this is the actual error, but it looked like a good place to start. As per the instructions for the forums, I haven't quoted the entire output here, but enclosed it in an attachment.