$ emerge -p sci-visualization/gnuplot

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

Calculating dependencies... done!

!!! The ebuild selected to satisfy ">=media-libs/gd-2.0.35-r3:2=[png]" has unmet requirements.
- media-libs/gd-2.2.2::gentoo_prefix USE="(prefix) (prefix-guest) zlib -fontconfig -jpeg -png -static-libs -tiff -truetype -webp -xpm"

  The following REQUIRED_USE flag constraints are unsatisfied:
    prefix? ( fontconfig )

(dependency required by "sci-visualization/gnuplot-5.0.3::gentoo_prefix[gd]" [ebuild])
(dependency required by "sci-visualization/gnuplot" [argument])