Add search path for CUDA on Arch.
CUDA is installed in /opt/cuda
on Arch. CMake only searches in /usr/local
(Debian/Ubuntu default) so it fails to find CUDA on Arch systems.
Here it can be seen the default is /opt/cuda
.
https://git.archlinux.org/svntogit/community.git/tree/trunk/PKGBUILD?h=packages/cuda