* IMPORTANT: 4 config files in '/etc/portage' need updating.
 * See the CONFIGURATION FILES section of the emerge
 * man page to learn how to update config files.
Calculating dependencies /

!!! Problem resolving dependencies for x11-drivers/nvidia-drivers from @selected
... done!

!!! The ebuild selected to satisfy "x11-drivers/nvidia-drivers" has unmet requirements.
- x11-drivers/nvidia-drivers-346.35::gentoo USE="X acpi multilib tools -gtk2 -gtk3 -pax_kernel -uvm" ABI_X86="64"

  The following REQUIRED_USE flag constraints are unsatisfied:
    tools? ( any-of ( gtk2 gtk3 ) )

  The above constraints are a subset of the following complete expression:
    tools? ( X any-of ( gtk2 gtk3 ) )

(dependency required by "@selected" [set])
(dependency required by "@world" [argument])