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

Calculating dependencies ... done!
Dependency resolution took 0.97 s (backtrack: 0/20).

[ebuild  N     ] sci-libs/libh2o-0.2.1-r1::gentoo  USE="-debug -static-libs" 284 KiB
[ebuild  N     ] sci-libs/libh2oxx-0.2-r1::gentoo  USE="-debug" 261 KiB

Total: 2 packages (2 new), Size of downloads: 544 KiB