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

Calculating dependencies ... done!
Dependency resolution took 0.99 s (backtrack: 0/20).

[ebuild  N     ] dev-libs/gf2x-1.3.0-r1:0/3::gentoo  USE="-custom-tune -fft -static-libs" CPU_FLAGS_X86="pclmul sse2 sse3 sse4_1 ssse3" 711 KiB
[ebuild  N     ] dev-libs/ntl-11.5.1-r4:0/44::gentoo  USE="threads -doc" 2251 KiB

Total: 2 packages (2 new), Size of downloads: 2961 KiB