portage-ng / portage / virtual / zlib / 1.3.1-r1
emerge -vp

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

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

[ebuild   R    ] virtual/zlib-1.3.1-r1:0/1::gentoo  USE="-static-libs" 0 KiB

Total: 1 package (1 reinstall), Size of downloads: 0 KiB

Wall time
1.937 s vs. 0.002 s for portage-ng