awesomebox ~ # emerge --ask dev-util/nvidia-cuda-toolkit

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  NS    ] sys-devel/gcc-4.8.5 [4.9.3] USE="cxx fortran (multilib) nls nptl openmp sanitize (-altivec) (-awt) -debug -doc (-fixed-point) -gcj -go -graphite (-hardened) (-libssp) -mudflap (-multislot) -nopie -nossp -objc -objc++ -objc-gc -regression-test -vanilla"
[ebuild   R   ~] x11-drivers/nvidia-drivers-340.96-r5  USE="uvm*"
[ebuild  N     ] dev-util/nvidia-cuda-toolkit-6.5.14  USE="-debugger -doc -eclipse -profiler"

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by dev-util/nvidia-cuda-toolkit-6.5.14::gentoo
# required by dev-util/nvidia-cuda-toolkit (argument)
>=x11-drivers/nvidia-drivers-340.96-r5 uvm

The following license changes are necessary to proceed:
 (see "package.license" in the portage(5) man page for more details)
# required by dev-util/nvidia-cuda-toolkit (argument)
=dev-util/nvidia-cuda-toolkit-6.5.14 NVIDIA-CUDA

Would you like to add these changes to your config files? [Yes/No] no





awesomebox ~ # cat /etc/portage/package.use/nvidia-cuda-toolkit
# required by dev-util/nvidia-cuda-toolkit-6.5.14::gentoo
# required by dev-util/nvidia-cuda-toolkit (argument)
>=x11-drivers/nvidia-drivers-340.96-r5 uvm



# required by dev-util/nvidia-cuda-toolkit (argument)
=dev-util/nvidia-cuda-toolkit-6.5.14 NVIDIA-CUDA


??
cat /etc/portage/package.license/nvidia-cuda-toolkit
# required by dev-util/nvidia-cuda-toolkit (argument)
=dev-util/nvidia-cuda-toolkit-6.5.14 NVIDIA-CUDA