dev-libs/Ice-3.3.1-r2 and dev-libs/Ice-3.4.0 ebuilds assign EAPI=2 in global scope, but EAPI=3 in pkg_postinst and pkg_postrm. PMS says: "All ebuild-defined variables discussed in this chapter [this includes EAPI] must be defined independently of any system, profile or tree dependent data, and must not vary depending upon the ebuild phase."
Since Ice-3.4.1 is stable, the two affected ebuilds could simply be removed.
No reply from maintainer, so I've fixed this myself.