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

Calculating dependencies ... done!
Dependency resolution took 1.03 s (backtrack: 0/20).

[ebuild  N     ] sci-libs/fftw-3.3.10-r1:3.0/3::gentoo  USE="openmp threads -doc -fortran -mpi -test (-zbus)" CPU_FLAGS_X86="avx avx2 fma3 sse sse2 -fma4" 4047 KiB
[ebuild  N     ] dev-libs/crypto++-8.9.0:0/8.9.0::gentoo  USE="asm openmp -static-libs -verify-sig" 9071 KiB
[ebuild  N     ] app-crypt/codecrypt-1.8-r3::gentoo  USE="cryptopp" 461 KiB

Total: 3 packages (3 new), Size of downloads: 13578 KiB