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

Calculating dependencies ... done!
Dependency resolution took 1.49 s (backtrack: 0/20).

[ebuild     U  ] dev-libs/mpc-1.4.1:0/3::gentoo [1.3.1:0/3::gentoo] USE="-static-libs -verify-sig" 520 KiB

Total: 1 package (1 upgrade), Size of downloads: 520 KiB