Being on ~amd64 after syncing, 'emerge -pvDuN world' command shows plenty similar errors (for each qt-related package), one of last ones is shown below.
How to resolve the issue? x11-libs/qt-core:4 ('ebuild', '/', 'x11-libs/qt-core-4.5.0_rc1', 'merge') pulled in by ~x11-libs/qt-core-4.5.0_rc1[qt3support,-debug] required by ('ebuild', '/', 'x11-libs/qt- sql-4.5.0_rc1', 'merge') ~x11-libs/qt-core-4.5.0_rc1[-debug] required by ('ebuild', '/', 'x11-libs/qt-script-4.5.0_rc1', 'merge') ~x11-libs/qt-core-4.5.0_rc1[-debug] required by ('ebuild', '/', 'x11-libs/qt-test-4.5.0_rc1', 'merge') (and 250 more)