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

Calculating dependencies ... done!
Dependency resolution took 1.05 s (backtrack: 0/20).

[ebuild  N     ] sci-electronics/ngspice-46::gentoo  USE="X klu openmp readline shared -debug -deprecated -doc -examples -fftw -tcl -test" 10259 KiB
[ebuild  N     ] sci-electronics/xcircuit-3.10.30-r2::gentoo  USE="-tcl" 1582 KiB

Total: 2 packages (2 new), Size of downloads: 11840 KiB